Would be High importance, but the 'kill gnome-screensaver' workaround is a reliable way to prevent the issue.
** Changed in: gnome-screensaver (Ubuntu) Importance: Undecided => Medium Status: Unconfirmed => Confirmed -- Lock Screen blanks screen instead of showing screensaver (on external monitor) https://launchpad.net/bugs/71030 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs