Audio monitor loses sync

I am consistently finding that the Audio Monitor output loses sync with the programme out. It will slowly drift out of time, getting more and more delayed. This happens whether the audio source is the program output or another mix.

Selecting a different audio mix (and optionally reselecting the one I want to monitor) jumps the audio back into sync, but it will just start the inevitable drift again.

I have never seen this happen.

Can you share the document that shows this behavior, please?

Also, what audio device do you use for audio monitoring?