It kind if sounds like the system is in partial sleep mode, or trying to get there. And that would make sense because when the bug occurs the lid is closed and you've disconnected the only other screen. So you're kind of asking for screen hotplugging (or switching back to it on the KVM) to wake the system. When you put it that way it's kind of not a bug, if the theory is right...
Can you please run 'gnome-tweaks' and check that: Gnome Tweaks > Power > Suspend when laptop lid is closed = OFF ? ** Package changed: xorg (Ubuntu) => ubuntu ** Changed in: ubuntu Status: New => Incomplete -- 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/1873510 Title: Blank screen when hotplugging monitors connected through DisplayPort dock To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1873510/+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