Ryzen 5 2600X w/ an RX580.
I detailed the issue here. Very persistent and tricky issue to track since there's no reproducible steps and it generates no errors. Happens under zero load, full load, after 5 minutes, 2 hours... it's about as random and as you can get. And yes, RAM is fine.

It's not that widespread as far as I can tell. I gave details elsewhere and included a few other places where people were reporting it. Not sure if it's tied to AMD GPUs, AMD CPUs, etc., but the common thread is that everyone I saw reporting it was using AMD.