With Plasma 6 (since at least 6.2, when I upgraded), the lock screen only displays with a second-long delay (potentially longer when battery is low) when I open my laptop's lid (waking up from suspend). During this interval, KDE shows a *live* desktop as though the screen was not locked and only switches back to the lock screen after that delay. This issue is only reproducible on X11. This seems like a pretty severe security risk? It would only take enough tries for my desktop to become vulnerable. For your reference, this issue had been found in GNOME and MATE before: - https://bugs.launchpad.net/ubuntu/+source/unity-2d/+bug/830348 - https://github.com/mate-desktop/mate-screensaver/issues/145 Only on Plasma, the delay can be much longer before the lock screen was shown. I have filmed this behaviour to better explain what I mean.
Created attachment 176936 [details] Lock screen delay
Thanks for the bug report! There already is an issue filed for this, marking it as a duplicate of that one. I can confirm that it does not happen with Wayland; the lock appears immediately. *** This bug has been marked as a duplicate of bug 485085 ***