Update. Today I experienced this: after suspending the laptop, now I do not experience broken rendering anymore. This happened once before. Everytime I reboot, it comes back.
I'll try to identify a pattern here. Also this is in the "Tweaks" application, gnome-shell does not have a theme associated (see screenshot) ** Attachment added: "Screenshot from 2019-10-01 15-47-58.png" https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1846201/+attachment/5293165/+files/Screenshot%20from%202019-10-01%2015-47-58.png -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1846201 Title: Rendering is delayed on laptop display (works in external display) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1846201/+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