I'm running latest neon, and when I start a stream ( youtube, web conferencins), the browser (eother firefox or chrome) start reproducing audio, and after a short period (seconds) the automatically mute. The only way I found to resume audio is to go to settings -> audio -> applications and unmute everyone singularly.
Is there a reason or a way to avoid this? because as you can imagine it is annoying since sometime I wait for a stream to begin and got no sound alert at all.

Confirmed, new clean installation