I feel like GPUs don't thermal throttle as gracefully as CPUs do. I have a desktop GPU and when it's at its max temperature for too long, eventually the graphics driver crashes. Meanwhile, CPUs are perfectly happy to run with inadequate cooling; they just thermal throttle.
I worry that it might actually be a software issue. GPU clock starts running slowly, software assumes that it will be running faster, two commands are issued but only one is processed, driver gets confused, driver crashes.