Currently running v3.1.1 of Audacity on Windows 11, one of the first things I noticed is the playhead can scroll below zero (but will disappear until it’s position is positive) during playback if you press the left key to rewind before the first second passes.
The audio playback and monitoring are not affected by this, but the playhead can be desynced and will not finish playback until it reaches the end, regardless of whether the audio has already finished playing or not, or if stopped manually.
I have not changed any setting prior to upgrading from 3.0.5, aside from also upgrading FFmpeg.
Thanks for the bug report. I’ve logged it.