I can reporduce this bug with a simple shape, applying RTAO node and tweaking the falloff distance. Machine will reboot.
I've also noticed this in painter with some older files, once I load them machine will re-boot.
I suspect it's something to do with my GPU (Drivers are up to date) or when Substance calls upon the GPU for certain functions.
All ram tests come up with no issues.
My config,
Windows 11 Pro - OS Build 22621.1848
13th Gen Intel(R) Core(TM) i9-13900K 3.00 GHz
128 GB (128 GB usable)
NVIDIA GeForce RTX 4090 24GB - Geforce Game Ready Driver - Version 536.23