The XorgLog files seem to show at least one of the monitors being redetected, like it was unplugged and replugged. If Xorg thinks that's happening then yes windows would move to one screen. Please try a different DisplayPort cable.
Also, please check that your gnome-shell process ID is the same before and after lock/suspend, by running: pidof gnome-shell both before and after. ** Package changed: xorg (Ubuntu) => gnome-shell (Ubuntu) ** Changed in: gnome-shell (Ubuntu) Status: New => Incomplete ** Tags added: multimonitor -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1884437 Title: Windows are resized and reordered upon resume from lock or suspend To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1884437/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs