Multichannel Opus fails to decode with DirectOpusAudioDecoding enabled

Two Opus-in-WebM buffers are embedded in this file and decoded twice each: once through decodeAudioData (Web Audio) and once by appending to a MediaSource. Nothing is fetched; no server is needed.

Expected on an unaffected build: all four green. With the DirectOpusAudioDecoding feature enabled, the 16-channel row fails in both columns while the 2-channel row passes.

running...
bufferdecodeAudioDataMediaSource.appendBuffer

How to toggle the feature

# force it ON  (reproduces the failure)
chrome --enable-features=DirectOpusAudioDecoding --user-data-dir=/tmp/p1

# force it OFF (everything passes)
chrome --disable-features=DirectOpusAudioDecoding --user-data-dir=/tmp/p2

The feature is delivered by the variations seed, so a profile may already have it on with no flag given, and it does not appear in chrome://flags. Note that an incognito window, a guest profile and a full browser restart all inherit the same seed, so none of them clear it.