No sound problems on sample rate change

MacBook Pro Max2
Sonoma 14.7.1
Cubase 14.0.5
RME UFX+

These problems persist regardless of plugins used, 3rd party or Cubase’s. As a result of this issue, I’ve moved back to Reaper for the time being. I sent this to Steinberg support a two weeks ago. All I received was a message that this issue needed to be checked out by the Steinberg team in Germany.

I can only get the audio buffer to work from 512 or maybe a bit lower (sometimes). Here’s the weird part… If I go any higher in Cubase with the buffer (e.g. 768), I get no sound and Audio Performance monitor goes red. The Real Time, ASIO Guard, and Peak levels don’t change but I don’t get sound and the solid red bar on the right side of Audio Performance Monitor. Usually raising the Audio Buffer results in less taxing of the CPU. However, in my case right now, that is not the case. I have tried changing the ASIO Guard, no effect (problem persists).