Something's (jelly)fishy with todays 42.0-1ubuntu4 update for me too. X11 only, no Wayland option which has been working well for the last couple of weeks. I'm on a Thinkpad with Intel UHD Graphics 620, which at some point had a nVidia eGPU connected to it -- though not recently due to the several known external screen issues. Suggested workaround #4 and #9 fixed it for me, but I've also found myself having to set "WaylandEnable=true" in /etc/gdm3/custom.conf otherwise the dual-screens don't scale right.
Something's (jelly)fishy with todays 42.0-1ubuntu4 update for me too. X11 only, no Wayland option which has been working well for the last couple of weeks. I'm on a Thinkpad with Intel UHD Graphics 620, which at some point had a nVidia eGPU connected to it -- though not recently due to the several known external screen issues. Suggested workaround #4 and #9 fixed it for me, but I've also found myself having to set "WaylandEnable= true" in /etc/gdm3/ custom. conf otherwise the dual-screens don't scale right.