Further to comment 5, I've had a further look in the live environment and it appears the screen isn't locked out when I switch user - so I can use Ctrl-Alt-F{1..8} to switch between things. This suggests to me that the screen-locking code path isn't getting tested when I try this from the Live USB.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1809117 Title: Screen corruption on "Lock Screen" or "Switch User" command To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1809117/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs