update sessions/0026/SESSION-0026.0-TRANSCRIPT-2026-06-27T15-26--INPROGRESS.md

sessions/0026/SESSION-0026.0-TRANSCRIPT-2026-06-27T15-26--INPROGRESS.md

@@ -86,6 +86,15 @@ Pure scrub logic kept separable + unit-tested; Playwright E2E extended to assert
 - **D3 residual still applies:** double-buffer kills the LOAD pause both directions; the reverse/turn-back FRAME
   asymmetry (morph src-start@0 vs loop tail@3s) and the ~loop-wrap seek remain (per-clip loop files would fully
   resolve if wanted).
+### Eyeball round 3 — audio-off bug (systematic-debugging), FIXED (1 commit)
+
+- **Bug:** audio turned off *sometimes* after landing on a new altitude. **Root cause (code-traced, not guessed):**
+  `fadeVolume` started a `setInterval` ramp that was **never cancelled**. `restAudio` fades the idle element to 0;
+  if within FADE_MS (500ms) that same element becomes the newly-landed ACTIVE scale (`assignElements` reuses one
+  element per soundtrack url), the stale fade-to-0 kept running and dragged the now-active element to silence —
+  hence "only sometimes." **Fix:** `cancelFade(el)` supersedes any in-flight fade when a new fade starts
+  (`fadeVolume`) or a direct volume is set (`ensurePlaying`). Added `window.__hefFade` seam + a deterministic E2E
+  that PROVES it (fails with the fix disabled, passes with it). Playwright **10 green**.
 - **Resume:** merge + `wgl-session-finalize` on operator go, OR next eyeball round of tweaks.
 
 ## Deferred decisions