[TF2] Playing without sound drivers causes voice chat bubbles to last forever

[CaptainGame17]

If TF2 is run without any sound drivers, voice chat visual indicators (the team-colored box on the HUD, and the bubble above their player model) will never disappear, unless the map is changed or a new server is joined. This causes problems with Spy in particular, where the bubble above their head can reveal their position while disguised or cloaked.

Here is a video of the bug.