I have exactly the same issue on my new M1 Air, Sonoma.
I noticed it when after couple of minutes the WSJT-X waterfall starts to be “blurry”, signal stations starts to be wider and wider. Decoding ratio drops. Audio recording gives similar effect like presented by VE7TZB.
In general, the audio works perfectly on my Mac, including Chinese usb audio card with Realtek chip (which I was forced to use instead of DigiRig). I also performed test with two USB hubs in between Mac and Chinese card, knowing there is a hub chip in the DigiRig. The DigiRig itself works good on Windows 10 on my old PC.
So in my opinion there is something wrong between Mac and DigiRig Mobile (in general or CM108 chip itself).
And I hope there is a solution better than stop using DigiRig.
73
Paweł
