I am not sure if the screen should be actually locked when suspend is initiated via "sudo pm-suspend". Also, in Xubuntu 18.04 pm-utils are not installed by default anymore.
Use one of the following commands instead: xfce4-session-logout --suspend systemctl suspend OR light-locker-command --lock && sudo pm-suspend ** Information type changed from Public Security to Public ** Changed in: xfce4-power-manager (Ubuntu) Status: Incomplete => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1741256 Title: Screen not locked on suspend To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xfce4-power-manager/+bug/1741256/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs