diff --git a/packages/core/src/runtime/init.test.ts b/packages/core/src/runtime/init.test.ts
index 1618d6736..54cd942a0 100644
--- a/packages/core/src/runtime/init.test.ts
+++ b/packages/core/src/runtime/init.test.ts
@@ -1487,13 +1487,36 @@ describe("initSandboxRuntimeModular", () => {
     const scheduleSpy = vi
       .spyOn(WebAudioTransport.prototype, "scheduleMediaElementPlayback")
       .mockResolvedValue(null);
+    const stopSpy = vi.spyOn(WebAudioTransport.prototype, "stopAll");
 
     const player = window.__player;
     player?.play();
-    player?.seek(0);
 
-    expect(scheduleSpy).toHaveBeenCalledTimes(1);
-    expect(scheduleSpy.mock.calls[0]?.[0]).toBe(hiddenAudio);
+    // A seek stops the transport itself, so the count is the measure: the
+    // visibility pass over a data-hidden element must add NO second stop while
+    // un-enrolled. The skips the reschedule exists to re-run are inert with the
+    // flag off, so the set it rebuilds is identical and the only observable
+    // effect is an audible stop-and-restart across the whole mix.
+    // The dirty flag is set by a data-hidden MUTATION, so the toggle is the
+    // gesture — a plain seek never reaches the reschedule at all.
+    hiddenAudio.removeAttribute("data-hidden");
+    player?.seek(1, { keepPlaying: true });
+    const unenrolled = stopSpy.mock.calls.length;
+
+    window.__hf?.setCanaries?.({ "audio-track-mute": true });
+    stopSpy.mockClear();
+    hiddenAudio.setAttribute("data-hidden", "");
+    player?.seek(2, { keepPlaying: true });
+    const enrolled = stopSpy.mock.calls.length;
+
+    expect(unenrolled).toBe(1);
+    expect(enrolled).toBe(unenrolled + 1);
+
+    // And the hidden clip is still audible to the transport un-enrolled: the
+    // canary flip handler reschedules, and with the flag off the hidden skip
+    // does not fire, so the element IS scheduled.
+    window.__hf?.setCanaries?.({ "audio-track-mute": false });
+    expect(scheduleSpy.mock.calls.map((call) => call[0])).toContain(hiddenAudio);
   });
 
   it("batches a mid-playback data-hidden toggle into exactly one Web Audio reschedule", () => {
@@ -1527,6 +1550,10 @@ describe("initSandboxRuntimeModular", () => {
 
     window.__timelines = { main: createMockTimeline(10) };
     initSandboxRuntimeModular();
+    // The reschedule IS the audio-track-mute feature — un-enrolled, hidden-ness
+    // does not change the active set, so nothing should stop or restart (see
+    // the un-enrolled test below). Enrol before asserting on it.
+    window.__hf?.setCanaries?.({ "audio-track-mute": true });
 
     const player = window.__player;
     // play() alone (no seek) already runs one visibility pass while the clock
@@ -1575,6 +1602,9 @@ describe("initSandboxRuntimeModular", () => {
 
     window.__timelines = { main: createMockTimeline(10) };
     initSandboxRuntimeModular();
+    // Enrolled: the stop-before-reschedule pairing this test pins only runs for
+    // the audio-track-mute feature.
+    window.__hf?.setCanaries?.({ "audio-track-mute": true });
     const player = window.__player;
     player?.play();
 
diff --git a/packages/core/src/runtime/init.ts b/packages/core/src/runtime/init.ts
index e71a2ea52..439d6f66f 100644
--- a/packages/core/src/runtime/init.ts
+++ b/packages/core/src/runtime/init.ts
@@ -42,7 +42,7 @@ import { applyVariableBindings } from "./applyVariableBindings";
 import { createColorGradingRuntime, type RuntimeColorGradingApi } from "./colorGrading";
 import { TransportClock } from "./clock";
 import { WebAudioTransport } from "./webAudioTransport";
-import { HF_AUDIO_GROUP_TAG } from "../audioGroups";
+import { HF_AUDIO_GROUP_TAG, isMemberGroupHidden } from "../audioGroups";
 import { clampNativeMediaVolume } from "../audioGain";
 import { quantizeTimeToFrame } from "../inline-scripts/parityContract";
 import { STUDIO_MANUAL_EDIT_GESTURE_ATTR } from "../editing/draftMarkers";
@@ -192,6 +192,11 @@ export function initSandboxRuntimeModular(): void {
   // render already does. Off until enrolled, so a composition carrying
   // `data-hidden` on an audio element keeps playing in preview meanwhile.
   const silenceHiddenAudioEnabled = (): boolean => canaries["audio-track-mute"] === true;
+  /** Hidden by an ancestor, or by the BUS this clip belongs to. The bus is
+   *  never an ancestor — membership is on the member's `data-audio-group` — so
+   *  `closest()` alone could not see a muted group, which the render drops. */
+  const isSilencedByHidden = (el: Element): boolean =>
+    el.closest("[data-hidden]") !== null || isMemberGroupHidden(el.ownerDocument, el);
   window.__hf.setCanaries = (states) => {
     const wasSilencing = silenceHiddenAudioEnabled();
     for (const [name, enabled] of Object.entries(states)) canaries[name] = enabled === true;
@@ -2048,7 +2053,12 @@ export function initSandboxRuntimeModular(): void {
         rawNode.style.display = "none";
       }
     }
-    if (hiddenAudioDirty && clock.isPlaying()) {
+    // Gated like every other consumer of this canary. The skips this reschedule
+    // exists to re-run (`silenceHiddenAudioEnabled() && …data-hidden`, below)
+    // are inert while the flag is off, so un-enrolled the whole stop/reschedule
+    // rebuilt an IDENTICAL active set — an audible stop-and-restart across the
+    // entire mix on every visibility toggle, at 100%, for a feature at 0%.
+    if (hiddenAudioDirty && silenceHiddenAudioEnabled() && clock.isPlaying()) {
       webAudio.stopAll();
       scheduleWebAudioForActiveClips();
     }
@@ -2995,7 +3005,7 @@ export function initSandboxRuntimeModular(): void {
           let foundActive = false;
           for (const rawEl of audioEls) {
             if (!(rawEl instanceof HTMLMediaElement) || !rawEl.isConnected) continue;
-            if (silenceHiddenAudioEnabled() && rawEl.closest("[data-hidden]")) continue;
+            if (silenceHiddenAudioEnabled() && isSilencedByHidden(rawEl)) continue;
             const start = Number.parseFloat(rawEl.dataset.start ?? "");
             const durAttr = parseStrictFiniteTimingNumber(rawEl.dataset.duration);
             const end = durAttr != null && durAttr > 0 ? start + durAttr : Infinity;
@@ -3103,7 +3113,7 @@ export function initSandboxRuntimeModular(): void {
     const audioEls = document.querySelectorAll("audio[data-start]");
     for (const rawEl of audioEls) {
       if (!(rawEl instanceof HTMLMediaElement) || !rawEl.isConnected) continue;
-      if (silenceHiddenAudioEnabled() && rawEl.closest("[data-hidden]")) continue;
+      if (silenceHiddenAudioEnabled() && isSilencedByHidden(rawEl)) continue;
       const compStart = Number.parseFloat(rawEl.dataset.start ?? "");
       if (!Number.isFinite(compStart)) continue;
       const mediaStart = readElementPlaybackStart(rawEl);