Just as a note, that bug still exists with kernel 5.4.7-1-default

On exit from X-Plane demo record in journal:
amdgpu 0000:07:00.0: GPU fault detected: 147 0x07587702 for process vivaldi-bin pid 23515 thread vivaldi-bi:cs0 pid 23544

And at least there are some progress and maybe on next year is bug fixed.