I've seen behaviour like that in a lot of peoples' Xorg logs. Maybe try a Wayland session instead?
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1806404 Title: After the screen turns off the machine has to be rebooted to get back to a working session Status in gnome-shell package in Ubuntu: Invalid Bug description: This is placeholder while I get more information. Somewhere to upload logs too. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1806404/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

