Make the live-run mirror survive lost phone-to-watch frames

Live frames ride sendMessage, which is reachable-only — and phone→watch
reachability drops exactly when the user is swiping on the phone (wrist
down). A frame that failed to send was staged but never retried until a
reachability edge, and a frame lost outright desynced the run until the
next human transition — sometimes forever, since a reconnect could even
re-send the stale staged frame and yank the peer backwards.

Four fixes, symmetric on both bridges and both run screens:

- A send that fails while nominally reachable now retries with a short
  backoff (a few times per staged message) instead of being swallowed.
- Receiving a frame that outranks the staged outbound one drops the
  staged frame, so a reconnect re-send can't move the run backwards;
  a delivery the staged frame outranks is ignored as stale.
- Every staleness comparison now tie-breaks the shared version sequence
  on the frame's wall-clock anchor (LiveProgress.isNewer) — after a
  lost frame both devices can mint the same version, and the later
  human action must win.
- Durable repair: when the absorbed workout doc shows sets completed
  beyond anything the open run screen recorded or followed, it jumps
  forward to the first unfinished set's work page — a lost frame now
  degrades to a briefly-stale page instead of a stuck one.

CHANGELOG.md

@@ -1,5 +1,7 @@
 **July 2026**
 
+Swiping through sets on the iPhone now reliably moves the watch along too, instead of the two drifting apart mid-workout.
+
 On Apple Watch, the workout screen now gives its whole display to the set and rest timer, without the form-guide figure shown on iPhone.
 
 Barbells and pull-up bars in the animated form guide now turn with the figure as the view circles, instead of hovering fixed on screen.

Shared/Connectivity/LiveProgress.swift

@@ -48,3 +48,19 @@ struct LiveProgress: Sendable, Equatable {
     /// Monotonic per-run sequence, so the mirror can drop a stale / out-of-order delivery.
     var version: Int
 }
+
+extension LiveProgress {
+    /// Strict "newer than" over the shared per-run sequence, tie-broken by the phase anchor.
+    /// The tie-break matters because the sequence isn't collision-free: each side catches its
+    /// counter up only from frames it *receives*, so after a lost frame both devices can mint
+    /// the same version independently. On a collision the later wall-clock action wins —
+    /// paired-device clock skew is sub-second, so the anchor orders genuine collisions
+    /// correctly. Equal version *and* equal anchor is the same frame redelivered: not newer.
+    func isNewer(thanVersion version: Int, start: Date) -> Bool {
+        self.version != version ? self.version > version : phaseStart > start
+    }
+
+    func isNewer(than other: LiveProgress) -> Bool {
+        isNewer(thanVersion: other.version, start: other.phaseStart)
+    }
+}

Workouts Watch App/Connectivity/WatchConnectivityBridge.swift

@@ -38,6 +38,12 @@ final class WatchConnectivityBridge: NSObject {
     /// wall-clock anchor, so a late re-send self-corrects on arrival rather than reading as stale.
     private var pendingLive: PendingLive?
 
+    /// In-flight backoff retry for a staged live message whose send *failed* (as opposed to
+    /// never being attempted because the peer was unreachable — that case is re-flushed by the
+    /// reachability/activation delegates). See `scheduleLiveRetry`.
+    private var liveRetryTask: Task<Void, Never>?
+    private var liveRetryAttempt = 0
+
     /// The latest live-run frame the *phone* sent, for the run we currently have open to apply
     /// (ephemeral; nil when the phone isn't driving). The watch's `ExerciseProgressView` reads
     /// this to follow a phone-driven transition; it's never persisted.
@@ -138,6 +144,7 @@ final class WatchConnectivityBridge: NSObject {
         var stamped = frame
         stamped.version = liveVersion
         pendingLive = .progress(stamped)
+        liveRetryAttempt = 0
         flushLive()
     }
 
@@ -147,6 +154,7 @@ final class WatchConnectivityBridge: NSObject {
     func sendLiveEnded(workoutID: String, logID: String) {
         guard let session, session.activationState == .activated else { return }
         pendingLive = .ended(workoutID: workoutID, logID: logID)
+        liveRetryAttempt = 0
         flushLive()
     }
 
@@ -156,6 +164,8 @@ final class WatchConnectivityBridge: NSObject {
     /// WatchConnectivity's background queue, so it must be nonisolated (@Sendable) — an
     /// inherited-@MainActor closure would trap (swift_task_checkIsolated) there.
     private func flushLive() {
+        liveRetryTask?.cancel()
+        liveRetryTask = nil
         guard let session, let pending = pendingLive,
               session.activationState == .activated, session.isReachable else { return }
         let payload: [String: Any]
@@ -165,14 +175,43 @@ final class WatchConnectivityBridge: NSObject {
         case .ended(let workoutID, let logID):
             payload = WCPayload.encodeLiveEnded(workoutID: workoutID, logID: logID)
         }
-        session.sendMessage(payload, replyHandler: nil, errorHandler: { @Sendable _ in })
+        session.sendMessage(payload, replyHandler: nil, errorHandler: { @Sendable [weak self] _ in
+            Task { @MainActor in self?.scheduleLiveRetry() }
+        })
     }
 
-    /// Apply a live-run frame the phone sent. Drops a stale one for the same run, and catches
-    /// our send counter up so the next frame we send outranks it (shared per-run sequence).
+    /// A send failed while the phone was nominally reachable. Without this the staged message
+    /// would sit until the next reachability/activation edge — which may never come mid-workout —
+    /// so back off briefly and re-flush, a handful of times per staged message (the edges still
+    /// re-flush after the retries are spent). Whatever is staged *when the retry fires* is sent,
+    /// so a newer frame staged meanwhile supersedes the failed one here too.
+    private func scheduleLiveRetry() {
+        guard pendingLive != nil, liveRetryTask == nil, liveRetryAttempt < 5 else { return }
+        liveRetryAttempt += 1
+        let delay = min(8.0, 0.5 * pow(2.0, Double(liveRetryAttempt - 1)))
+        liveRetryTask = Task { [weak self] in
+            try? await Task.sleep(for: .seconds(delay))
+            guard let self, !Task.isCancelled else { return }
+            self.liveRetryTask = nil
+            self.flushLive()
+        }
+    }
+
+    /// Apply a live-run frame the phone sent. Catches our send counter up first (shared per-run
+    /// sequence), then arbitrates against our own staged outbound frame for the same run: if the
+    /// incoming frame outranks it, drop the staged one (so a later reconnect can't re-send stale
+    /// state and yank the run backwards); if the *staged* frame outranks the delivery — a late or
+    /// version-collided arrival predating our own latest action — ignore the incoming frame.
+    /// Finally drops anything not newer than what we're already showing (redeliveries included).
     private func applyIncomingLive(_ frame: LiveProgress) {
         liveVersion = max(liveVersion, frame.version)
-        if let current = liveIncoming, current.logID == frame.logID, frame.version < current.version { return }
+        if case .progress(let staged) = pendingLive, staged.logID == frame.logID {
+            guard !staged.isNewer(than: frame) else { return }
+            pendingLive = nil
+            liveRetryTask?.cancel()
+            liveRetryTask = nil
+        }
+        if let current = liveIncoming, current.logID == frame.logID, !frame.isNewer(than: current) { return }
         liveIncoming = frame
     }
 

Workouts Watch App/Views/ExerciseProgressView.swift

@@ -61,8 +61,15 @@ struct ExerciseProgressView: View {
     /// A human swipe leaves this `nil` (→ treated as human); programmatic moves set it.
     @State private var pageChangeCause: PageChangeCause?
 
-    /// Highest remote frame version we've applied, so a redelivery doesn't re-jump.
+    /// Highest remote frame we've applied — version plus its anchor tie-break (see
+    /// `LiveProgress.isNewer`) — so a redelivery or collided stale frame doesn't re-jump.
     @State private var lastAppliedVersion = 0
+    @State private var lastAppliedStart = Date.distantPast
+
+    /// Highest completed-set count this screen has itself recorded or followed via a live
+    /// frame — the baseline `repairFromDurable` compares an absorbed doc against, so a
+    /// durable echo of our own progress (or of a frame we followed) never triggers a jump.
+    @State private var knownStateIndex: Int
 
     /// When a remote frame drove us to a page, that page's timer anchors to the *sender's*
     /// wall clock (`remoteAnchorStart`/`End`) instead of local `now` — so delivery latency
@@ -100,6 +107,7 @@ struct ExerciseProgressView: View {
         let log = doc.wrappedValue.logs.first { $0.id == logID }
         let sets = max(1, log?.sets ?? 1)
         _setCount = State(initialValue: sets)
+        _knownStateIndex = State(initialValue: max(0, log?.currentStateIndex ?? 0))
 
         let notStarted = (log?.status ?? WorkoutStatus.notStarted.rawValue) == WorkoutStatus.notStarted.rawValue
         // The Ready page always leads the flow (except in the screenshot host). A
@@ -141,6 +149,12 @@ struct ExerciseProgressView: View {
         return base + completed * 2
     }
 
+    /// Completed-set count a given page implies — the same math `recordProgress` records
+    /// (capped at `setCount − 1`; only an explicit Done marks the final set).
+    private func completedSets(for pageIndex: Int) -> Int {
+        min(max(0, (pageIndex - base + 1) / 2), setCount - 1)
+    }
+
     /// Position within the work/rest cycle for the current page — `nil` on the Ready
     /// and Finish pages (which show no dots).
     private var currentCycleIndex: Int? {
@@ -257,6 +271,9 @@ struct ExerciseProgressView: View {
         .onChange(of: incomingFrame) { _, frame in
             if let frame { applyIncoming(frame) }
         }
+        .onChange(of: log?.currentStateIndex) { _, _ in
+            repairFromDurable()
+        }
         .onAppear {
             guard !didRestorePage else { return }
             if startsResumed {
@@ -305,10 +322,15 @@ struct ExerciseProgressView: View {
     /// for a remote One More) without re-broadcasting or re-recording it — the phone owns the
     /// durable write, which arrives separately over the document sync.
     private func applyIncoming(_ frame: LiveProgress) {
-        guard didRestorePage, frame.logID == logID, frame.version > lastAppliedVersion else { return }
+        guard didRestorePage, frame.logID == logID,
+              frame.isNewer(thanVersion: lastAppliedVersion, start: lastAppliedStart) else { return }
         lastAppliedVersion = frame.version
+        lastAppliedStart = frame.phaseStart
         if frame.setCount != setCount { setCount = frame.setCount }
         let target = page(forPhase: frame.phase, setIndex: frame.setIndex)
+        // A followed frame is progress this screen now *knows*, so a durable echo of the
+        // same transition can't re-trigger the repair jump (a remote reset re-baselines).
+        knownStateIndex = frame.phase == .ready ? 0 : max(knownStateIndex, completedSets(for: target))
         // Anchor the target page's timer to the sender's wall clock, not local now, so the
         // displayed countdown matches regardless of how long the frame took to arrive.
         remoteAnchorPage = target
@@ -319,6 +341,27 @@ struct ExerciseProgressView: View {
         withAnimation { currentPage = target }
     }
 
+    /// Durable-state safety net for the ephemeral mirror. A peer's swipe frame can be lost
+    /// (`sendMessage` is reachable-only and the retry can run dry), but its durable write still
+    /// arrives via the application context and is absorbed into `doc` by the parent list. When
+    /// the absorbed doc shows sets completed beyond anything this screen has recorded or
+    /// followed, jump forward to the first unfinished set's work page so the flow can't stay
+    /// stuck on a stale phase. Forward-only — progress is monotonic, so a same-or-behind doc
+    /// is our own write echoing back — and only while the run is still in progress.
+    private func repairFromDurable() {
+        guard didRestorePage, let log,
+              log.status == WorkoutStatus.inProgress.rawValue else { return }
+        let completed = log.currentStateIndex
+        guard completed > knownStateIndex else { return }
+        knownStateIndex = completed
+        if log.sets > setCount { setCount = log.sets }
+        let target = base + min(max(0, completed), setCount - 1) * 2
+        guard target > currentPage else { return }
+        clearRemoteAnchor()
+        pageChangeCause = .remote
+        withAnimation { currentPage = target }
+    }
+
     /// Drop the remote anchor when a local transition moves us off the remote-driven page,
     /// so the next phase counts off local `now` (and a swipe back doesn't reuse a stale anchor).
     private func clearRemoteAnchor() {
@@ -478,6 +521,7 @@ struct ExerciseProgressView: View {
     /// plan, and slide forward into the bonus set's work phase.
     private func addSet() {
         let newCount = setCount + 1
+        knownStateIndex = max(knownStateIndex, newCount - 1)
 
         if let i = doc.logs.firstIndex(where: { $0.id == logID }) {
             doc.logs[i].sets = newCount
@@ -505,8 +549,8 @@ struct ExerciseProgressView: View {
     /// swiping back — or a transient TabView snap to page 0 — never un-counts a set.
     private func recordProgress(for pageIndex: Int) {
         if showsReady && pageIndex == 0 { return }   // Ready page records nothing
-        let cycleIndex = pageIndex - base
-        let reached = min(max(0, (cycleIndex + 1) / 2), setCount - 1)
+        let reached = completedSets(for: pageIndex)
+        knownStateIndex = max(knownStateIndex, reached)
 
         guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
         guard reached > doc.logs[i].currentStateIndex else { return }
@@ -527,6 +571,7 @@ struct ExerciseProgressView: View {
         guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
         let log = doc.logs[i]
         // Skip the write if it's already pristine (e.g. landing on Ready before any set).
+        knownStateIndex = 0
         guard log.currentStateIndex != 0
                 || log.status != WorkoutStatus.notStarted.rawValue else { return }
         doc.logs[i].currentStateIndex = 0
@@ -537,6 +582,7 @@ struct ExerciseProgressView: View {
     }
 
     private func completeExercise() {
+        knownStateIndex = max(knownStateIndex, setCount)
         guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
         doc.logs[i].currentStateIndex = setCount
         doc.logs[i].transition(to: .completed)

Workouts/Connectivity/LiveRunState.swift

@@ -34,9 +34,9 @@ final class LiveRunState {
         return c
     }
 
-    /// Apply an incoming frame, dropping a stale one for the same run.
+    /// Apply an incoming frame, dropping a stale (or redelivered) one for the same run.
     func apply(_ frame: LiveProgress) {
-        if let c = current, c.logID == frame.logID, frame.version < c.version { return }
+        if let c = current, c.logID == frame.logID, !frame.isNewer(than: c) { return }
         current = frame
     }
 

Workouts/Connectivity/PhoneConnectivityBridge.swift

@@ -38,6 +38,12 @@ final class PhoneConnectivityBridge: NSObject {
     /// wall-clock anchor, so a late re-send self-corrects on arrival rather than reading as stale.
     private var pendingLive: PendingLive?
 
+    /// In-flight backoff retry for a staged live message whose send *failed* (as opposed to
+    /// never being attempted because the peer was unreachable — that case is re-flushed by the
+    /// reachability/activation delegates). See `scheduleLiveRetry`.
+    private var liveRetryTask: Task<Void, Never>?
+    private var liveRetryAttempt = 0
+
     private var context: ModelContext { container.mainContext }
 
     init(container: ModelContainer, syncEngine: SyncEngine, liveRunState: LiveRunState) {
@@ -146,6 +152,7 @@ final class PhoneConnectivityBridge: NSObject {
         var stamped = frame
         stamped.version = liveVersion
         pendingLive = .progress(stamped)
+        liveRetryAttempt = 0
         flushLive()
     }
 
@@ -155,6 +162,7 @@ final class PhoneConnectivityBridge: NSObject {
     func sendLiveEnded(workoutID: String, logID: String) {
         guard let session, session.activationState == .activated else { return }
         pendingLive = .ended(workoutID: workoutID, logID: logID)
+        liveRetryAttempt = 0
         flushLive()
     }
 
@@ -164,6 +172,8 @@ final class PhoneConnectivityBridge: NSObject {
     /// WatchConnectivity's background queue, so it must be nonisolated (@Sendable) — an
     /// inherited-@MainActor closure would trap (swift_task_checkIsolated) there.
     private func flushLive() {
+        liveRetryTask?.cancel()
+        liveRetryTask = nil
         guard let session, let pending = pendingLive,
               session.activationState == .activated, session.isReachable else { return }
         let payload: [String: Any]
@@ -173,13 +183,42 @@ final class PhoneConnectivityBridge: NSObject {
         case .ended(let workoutID, let logID):
             payload = WCPayload.encodeLiveEnded(workoutID: workoutID, logID: logID)
         }
-        session.sendMessage(payload, replyHandler: nil, errorHandler: { @Sendable _ in })
+        session.sendMessage(payload, replyHandler: nil, errorHandler: { @Sendable [weak self] _ in
+            Task { @MainActor in self?.scheduleLiveRetry() }
+        })
+    }
+
+    /// A send failed while the watch was nominally reachable. Without this the staged message
+    /// would sit until the next reachability/activation edge — which may never come mid-workout —
+    /// so back off briefly and re-flush, a handful of times per staged message (the edges still
+    /// re-flush after the retries are spent). Whatever is staged *when the retry fires* is sent,
+    /// so a newer frame staged meanwhile supersedes the failed one here too.
+    private func scheduleLiveRetry() {
+        guard pendingLive != nil, liveRetryTask == nil, liveRetryAttempt < 5 else { return }
+        liveRetryAttempt += 1
+        let delay = min(8.0, 0.5 * pow(2.0, Double(liveRetryAttempt - 1)))
+        liveRetryTask = Task { [weak self] in
+            try? await Task.sleep(for: .seconds(delay))
+            guard let self, !Task.isCancelled else { return }
+            self.liveRetryTask = nil
+            self.flushLive()
+        }
     }
 
     /// Apply a frame the watch sent. Catch our send counter up to it first, so the next frame
     /// we send outranks it and the shared per-run sequence keeps increasing across devices.
+    /// Then arbitrate against our own staged outbound frame for the same run: if the incoming
+    /// frame outranks it, drop the staged one (so a later reconnect can't re-send stale state
+    /// and yank the run backwards); if the *staged* frame outranks the delivery — a late or
+    /// version-collided arrival predating our own latest action — ignore the incoming frame.
     private func applyIncomingLive(_ frame: LiveProgress) {
         liveVersion = max(liveVersion, frame.version)
+        if case .progress(let staged) = pendingLive, staged.logID == frame.logID {
+            guard !staged.isNewer(than: frame) else { return }
+            pendingLive = nil
+            liveRetryTask?.cancel()
+            liveRetryTask = nil
+        }
         liveRunState.apply(frame)
     }
 

Workouts/Views/WorkoutLogs/ExerciseProgressView.swift

@@ -82,8 +82,15 @@ struct ExerciseProgressView: View {
     /// A human swipe leaves this `nil` (→ treated as human); programmatic moves set it.
     @State private var pageChangeCause: PageChangeCause?
 
-    /// Highest remote frame version we've applied, so a redelivery doesn't re-jump.
+    /// Highest remote frame we've applied — version plus its anchor tie-break (see
+    /// `LiveProgress.isNewer`) — so a redelivery or collided stale frame doesn't re-jump.
     @State private var lastAppliedVersion = 0
+    @State private var lastAppliedStart = Date.distantPast
+
+    /// Highest completed-set count this screen has itself recorded or followed via a live
+    /// frame — the baseline `repairFromDurable` compares an absorbed doc against, so a
+    /// durable echo of our own progress (or of a frame we followed) never triggers a jump.
+    @State private var knownStateIndex: Int
 
     /// When a remote frame drove us to a page, that page's timer anchors to the *sender's*
     /// wall clock (`remoteAnchorStart`/`End`) instead of local `now` — so delivery latency
@@ -125,6 +132,7 @@ struct ExerciseProgressView: View {
         let log = doc.wrappedValue.logs.first { $0.id == logID }
         let sets = max(1, log?.sets ?? 1)
         _setCount = State(initialValue: sets)
+        _knownStateIndex = State(initialValue: max(0, log?.currentStateIndex ?? 0))
 
         // The Ready page always leads the flow. A not-started run opens on it; an
         // in-progress run opens on its first unfinished set and re-asserts that page past
@@ -165,6 +173,12 @@ struct ExerciseProgressView: View {
         return base + completed * 2
     }
 
+    /// Completed-set count a given page implies — the same math `recordProgress` records
+    /// (capped at `setCount − 1`; only an explicit Done marks the final set).
+    private func completedSets(for pageIndex: Int) -> Int {
+        min(max(0, (pageIndex - base + 1) / 2), setCount - 1)
+    }
+
     /// Position within the work/rest cycle for the current page — `nil` on the Ready
     /// and Finish pages (which show no dots).
     private var currentCycleIndex: Int? {
@@ -301,6 +315,9 @@ struct ExerciseProgressView: View {
         .onChange(of: incomingFrame) { _, frame in
             if let frame { applyIncoming(frame) }
         }
+        .onChange(of: log?.currentStateIndex) { _, _ in
+            repairFromDurable()
+        }
         .onAppear {
             guard !didRestorePage else { return }
             if startsResumed {
@@ -375,10 +392,15 @@ struct ExerciseProgressView: View {
     /// for a remote One More) without re-broadcasting or re-recording it — the watch owns the
     /// durable write, which arrives separately over the document sync.
     private func applyIncoming(_ frame: LiveProgress) {
-        guard didRestorePage, frame.logID == logID, frame.version > lastAppliedVersion else { return }
+        guard didRestorePage, frame.logID == logID,
+              frame.isNewer(thanVersion: lastAppliedVersion, start: lastAppliedStart) else { return }
         lastAppliedVersion = frame.version
+        lastAppliedStart = frame.phaseStart
         if frame.setCount != setCount { setCount = frame.setCount }
         let target = page(forPhase: frame.phase, setIndex: frame.setIndex)
+        // A followed frame is progress this screen now *knows*, so a durable echo of the
+        // same transition can't re-trigger the repair jump (a remote reset re-baselines).
+        knownStateIndex = frame.phase == .ready ? 0 : max(knownStateIndex, completedSets(for: target))
         // Anchor the target page's timer to the sender's wall clock, not local now, so the
         // displayed countdown matches regardless of how long the frame took to arrive.
         remoteAnchorPage = target
@@ -389,6 +411,27 @@ struct ExerciseProgressView: View {
         withAnimation { currentPage = target }
     }
 
+    /// Durable-state safety net for the ephemeral mirror. A peer's swipe frame can be lost
+    /// (`sendMessage` is reachable-only and the retry can run dry), but its durable write still
+    /// arrives via the document sync and is absorbed into `doc` by the parent. When the
+    /// absorbed doc shows sets completed beyond anything this screen has recorded or
+    /// followed, jump forward to the first unfinished set's work page so the flow can't stay
+    /// stuck on a stale phase. Forward-only — progress is monotonic, so a same-or-behind doc
+    /// is our own write echoing back — and only while the run is still in progress.
+    private func repairFromDurable() {
+        guard didRestorePage, let log,
+              log.status == WorkoutStatus.inProgress.rawValue else { return }
+        let completed = log.currentStateIndex
+        guard completed > knownStateIndex else { return }
+        knownStateIndex = completed
+        if log.sets > setCount { setCount = log.sets }
+        let target = base + min(max(0, completed), setCount - 1) * 2
+        guard target > currentPage else { return }
+        clearRemoteAnchor()
+        pageChangeCause = .remote
+        withAnimation { currentPage = target }
+    }
+
     /// Drop the remote anchor when a local transition moves us off the remote-driven page,
     /// so the next phase counts off local `now` (and a swipe back doesn't reuse a stale anchor).
     private func clearRemoteAnchor() {
@@ -596,6 +639,7 @@ struct ExerciseProgressView: View {
     /// plan, and slide forward into the bonus set's work phase.
     private func addSet() {
         let newCount = setCount + 1
+        knownStateIndex = max(knownStateIndex, newCount - 1)
 
         if let i = doc.logs.firstIndex(where: { $0.id == logID }) {
             doc.logs[i].sets = newCount
@@ -623,8 +667,8 @@ struct ExerciseProgressView: View {
     /// TabView snap to page 0 — never un-counts a set.
     private func recordProgress(for pageIndex: Int) {
         if showsReady && pageIndex == 0 { return }   // Ready page records nothing
-        let cycleIndex = pageIndex - base
-        let reached = min(max(0, (cycleIndex + 1) / 2), setCount - 1)
+        let reached = completedSets(for: pageIndex)
+        knownStateIndex = max(knownStateIndex, reached)
 
         guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
         guard reached > doc.logs[i].currentStateIndex else { return }
@@ -644,6 +688,7 @@ struct ExerciseProgressView: View {
     private func resetExercise() {
         guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
         let log = doc.logs[i]
+        knownStateIndex = 0
         // Skip the write if it's already pristine (e.g. landing on Ready before any set).
         guard log.currentStateIndex != 0
                 || log.status != WorkoutStatus.notStarted.rawValue else { return }
@@ -655,6 +700,7 @@ struct ExerciseProgressView: View {
     }
 
     private func completeExercise() {
+        knownStateIndex = max(knownStateIndex, setCount)
         guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
         doc.logs[i].currentStateIndex = setCount
         doc.logs[i].transition(to: .completed)

WorkoutsTests/LiveProgressOrderingTests.swift

@@ -0,0 +1,47 @@
+import Foundation
+import Testing
+@testable import Workouts
+
+/// Pins the live-mirror staleness ordering (`LiveProgress.isNewer`): the shared per-run
+/// version sequence decides, and the phase anchor breaks ties. The tie-break exists
+/// because the sequence isn't collision-free — each side catches its counter up only from
+/// frames it *receives*, so after a lost frame both devices can mint the same version
+/// independently, and the later wall-clock action must win. Equal version *and* equal
+/// anchor is the same frame redelivered, which must NOT rank as newer (a redelivery would
+/// otherwise re-jump the follower's page).
+struct LiveProgressOrderingTests {
+    private static let t0 = Date(timeIntervalSince1970: 1_700_000_000)
+
+    private func frame(version: Int, start: Date) -> LiveProgress {
+        LiveProgress(workoutID: "W", logID: "L", exerciseName: "Bench", phase: .work,
+                     setIndex: 0, setCount: 3, detail: "8 reps",
+                     phaseStart: start, phaseEnd: nil, version: version)
+    }
+
+    @Test func higherVersionWinsRegardlessOfAnchor() {
+        let older = frame(version: 3, start: Self.t0.addingTimeInterval(10))
+        let newer = frame(version: 4, start: Self.t0)   // earlier anchor, higher version
+        #expect(newer.isNewer(than: older))
+        #expect(!older.isNewer(than: newer))
+    }
+
+    @Test func collidedVersionsTieBreakOnAnchor() {
+        let phoneFrame = frame(version: 4, start: Self.t0)
+        let watchFrame = frame(version: 4, start: Self.t0.addingTimeInterval(2))
+        #expect(watchFrame.isNewer(than: phoneFrame))
+        #expect(!phoneFrame.isNewer(than: watchFrame))
+    }
+
+    @Test func redeliveryIsNotNewer() {
+        let sent = frame(version: 4, start: Self.t0)
+        #expect(!sent.isNewer(than: sent))
+    }
+
+    @Test func versionAndStartOverloadMatchesFrameOverload() {
+        let f = frame(version: 4, start: Self.t0)
+        #expect(f.isNewer(thanVersion: 3, start: Self.t0.addingTimeInterval(99)))
+        #expect(f.isNewer(thanVersion: 4, start: Self.t0.addingTimeInterval(-1)))
+        #expect(!f.isNewer(thanVersion: 4, start: Self.t0))
+        #expect(!f.isNewer(thanVersion: 5, start: .distantPast))
+    }
+}