Same sort of thing happens to me whatever evolution of amdgpu in various
kernels I've been using in the last year or so.

The outcome is very random, either crashes my system or logs me out of Gnome.

It happens if the screen goes blank or even worse, when I deactivate all lock
screens or screensavers, if I just turn the TV off, have a nap and back on,
Gnome will be at log in screen, with previous session terminated.