Sorry Reuben, its occurring on the current develop tip, with a 9 year old Intel iMac running 10.15.7. The issue was originally reported to me by a user with a MacBook (platform unspecified).
I’ve just done a bit more testing and found the issue is only occurring for me with a multi output composite audio device created in the Audio MIDI Setup app. I’ll check with my user to see if they were also using a composite device (I had assumed not because they usually use my app to test their own device drivers).
Apologies again for my lack of thoroughness, and the consequent sub-optimal use of your time.