I’m getting this as well, very often, only thing to do is close audacity and reopen it. Often it’s not recognising that i have headphones plugged in either and have to go to preferences and select headphones for playback devices. I’ve never had so many issues with an update going back over a dozen years using Audacity.
I also have this issue after getting a new Mac (macOS 13.0.1 and Audacity 3.2.1).
I have a Samsun Q2U microphone which has analog direct monitor mode, where I plug headphones into the microphone and get zero latency monitoring.
With Audacity 3.1.3, I have the following behaviour:
record device set to mic, playback set to mic: monitoring stops while recording and starts again as soon as recording stops
record device set to mic, playback set to anything else: monitoring continues while recording (desired behaviour)
With Audacity 3.2.1, if I start recording, monitoring stops, regardless of what the playback device is set to, or whether recording mono or stereo. It does not return when recording stops. To re-enable the monitoring I have to either unplug and reconnect the microphone, or deselect and reselect “Thru” in Audio/MIDI Settings:
Please let me know if I can provide any more information.