Comment 2 for bug 1803885

For future reference (probably my own), if anyone else has this issue.

Although the problem doesn't entirely go away. There is still some strange artifacting and ocassionally black foreground in windows. Most likely memory corruption, as a reboot cures it.

In /etc/gdm3/custom.conf change the line
[daemon]
WaylandEnable=true
to
WaylandEnable=false