That's not surprising. Any bug in MATE, or bug experienced via Marco, might be years old and also present in Ubuntu 19.10. But more likely this bug is the combined result of MATE + AMD meaning it might have only just become noticeable in 20.04.
** Also affects: mesa (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-amdgpu in Ubuntu. https://bugs.launchpad.net/bugs/1882525 Title: [amdgpu] MATE desktop is corrupted upon login on Ryzen APU To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/marco/+bug/1882525/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp