[I work at Microsoft, so please contact me internally if you need more info.]
I am using the "Remote Desktop client for Windows" to connect to a Windows AVD. After connection, the remote audio input and output both work. But after the remote audio input is unused for a few seconds (i.e. no application is actively using it), it stops working until I either reconnect or restart the Windows Audio Service on the AVD.
Note that the remote audio output continues to work fine. It's just the input that stops working.
This problem does not happen for Teams specifically, but I suspect that's because it uses WebRTC.