I have had something similar happen. I think it is a Windows issue, as it did not happen on the first few Win10 versions.
If I set my RME Raydat as Windows Audio in and out, everything is fine until i start to change the buffer size on the RME.
Then I same kind of digital distortion.
I tried updating the driver for the RME and that fixed the issue until I changed the buffer size again.
Disabling these WDM audio channels in the RME driver and audio is back, no problem changing buffer size and in general better performance.
My Yamaha keyboard has a audio device build in, so i set windows to use that for it’s audio and use totalmix to monitor those inputs.
So, simply said try avoid using your RME for any Windows sound, use it purely for ASIO.
It might be something completely different, but it is worth a try. You may have to fiddle a little back and forth with the buffer size to reset or boot the computer before you see any effect.