How did you install it?
Download?
pip
apt / apt-get ?
I just installed it via apt (Ubuntu 20.04 gnome, Ryzen 5 16 GB RAM) and played it for half an hour or so (I only play Klondike 3 card deal) and it seemed okay to me - but that’s nothing…
I know you ran memtest86, but would it be worth while trying (I’m assuming this is probably 4 x 4 GB DDR3 DIMM modules?) to run it on say just a pair @ 8 GB and see if it gets repeated… then the other pair?
Also - maybe run a performance monitor and something showing temp sensors, while you’re playing?