I was in a game tonight on Dome where I muted a player (appropriately named) “Sonar”, yet despite the Muted status, and even the Red Speaker icon via the Scoreboard, he was still audible to me. I even un-muted and re-muted him during the match, and he’s still audible, as is shown in the video attached. It’s a 2 minute video, so the first half is me re-muting, and he speaks a few times sporadically during the video, but is more audible toward the end.
I’ve never experienced this before today’s Summer Squash 3 patch, and I mute these quarterbacks on the daily.
Edit: I should also mention that the mute / speaker icon was flashing between red and white while he was speaking if I had the scorecard window up.