I wrote on AMD help forums and I have the exact same thing, except that I dont run into problems with pre 188.8.131.52 agesa. Im more stable with older agesa. Even on stock/auto settings I cannot run karhu or TM5. But everytime I ran those 2 tests I had hwinfo64 (6.40-4330) open in the background to try and catch whea errors before reboot, but I was unable to log anything. It was straight reboots.
I have a ROG strix B450-F gaming + ryzen 5900x + 4x8gb gskill ripjaws 3200mhz Cl14 giving some whea error and reboots only in karhu mem benchmarkand TM5. Daily usage is fine, no crashes, bluescreen nor stuttering. I can even run prime95, membench, cb23, cb20 without errors:
Please upgrade HWiNFO to v6.43 Beta.