I have a similar problem.
Cakewalk works just fine until i play back something. Sometimes suddenly the PC switches off and reboot.
A reliable way to reproduce this error:
Start Cakewalk (2021.06 Build 53, 64 bit)
Create new Project (Empty Project.cwt)
Add SI-Drum Kit
Add some Notes (e.g. just one B4)
Press the Play-Button
Press the Return to Start Button (Ctrl+Pos1)
Press Stop
This works every time. Sadly i can't find any additional information. Not even a blue screen.
I can play and stop without a problem. I assume that it only crashes, when i do this play-stop procedure, but until now i didn't pay attention to it while working with Cakewalk.
The CPU is at about 6%, RAM 25%. I can render with Blender and Resolve without any troubles, so i don't think this is related to my PC. Maybe something very audio related.