FYI: ALSA: "Volume muted" with Anki 2.1.22 on Debian (almost) testing bullseye

I’ve been slowly updating my Debian from stable (buster) to testing (bullseye). Almost done. This or last month, sound stopped playing. Every time Anki tries to play sound, the notifiction “Volume muted” appears, and ALSA’s volume for “Master”, “Headphones” and “Front” are, indeed, muted.

For Firefox, I am using apulse, because PulseAudio crashes all the time.

Firefox and usually MPV worked, but sometimes MPV and always Anki would cause that notification to appear.

Solved by downgrading PulseAudio from 13.0-5 to 12.2-4.