Client beta: 3.9.50
Server beta: 2022.03.09.0225
This occurs in live or recorded shows.
Volume fades slowly in and out, from crystal clear to somewhat muted.
This cycles repeatedly throughout a show.
Shows no errors in logs.
Tried all the client betas to February (2.24.429)
Does appear to happen in the ATV beta clients as far back so I suspect it's in the window server became it only showed up in the last 48 hours or so