Weird (reproduceable) system crash during "Legend of Grimrock"

Hello everyone!
I am not even sure how to describe this issue, not even sure if it’s gaming-related, software-related, or hardware-related… so I’ll give it my best shot:
I’ve been playing legend of grimrock for the past few hours and every time I go near the gate of the first stage (?) the system just… not even sure what it does. Completely looses power? Screen goes dark, all fans inside the case seemingly stop, keyboard light turns of, sounds cuts out, basically everything shuts down - however the case/powerbutton light stays on, indicating that there is still some power going to the mainboard. Yet I can’t use the reset system button as it doesn’t work (most of the time). So basically I have to restart the PC by unplugging and replugging the power cord.
I tried to reproduce this error and was able to “crash the system” the same way every time I approach this specific door.
Also kept an eye on temperatures, but since the game isn’t exactly demanding, they were all hovering around 40°C
Now, this sounds like a Software bug which would be avoidable by just not playing the game… but the way it plays out is just too weird to ignore…
any ideas?

here are my specs:
Ryzen 7 Pro 4750G (that’s the Renoir desktop APU)
G.Skill SniperX 16GB, DDR4-3600
ASRock B550M-ITC/ac
Scythe Mugen 5 Rev2
SF450 Platinum
random 12cm system fan + NF-A12x15 PWM
crucial p5 nvme 500gb + seagate 4tb hdd

Running Kernel 5.9.16-1