SUMMARY

I am currently using openSUSE Leap 15.3 with KDE repositories, so I installed updates for Plasma 5.24.90. After the update, I realized that kwin and a bunch of other packages are still at 5.24.5, but things worked smoothly regardless,

Then, the day before yesterday I got the missing updates to 5.24.90:
gmenudbusmenuproxy
layer-shell-qt5
libKScreenLocker5
plasma5-integration-plugin
xembedsniproxy
xdg-desktop-portal-kde
libKF5Screen7
libkscreen2-plugin
kwayland-integration
kscreenlocker
kwin5
plasma5-workspace-libs
plasma5-workspace
plasma5-session(-wayland)
(note that I use X11)

I installed those and made no other tweaks. Since then, whenever I try to lock my screen (or it locks automatically), instead of the lock screen I get the "switch to TTY and unlock with loginctl" message :(

There are some QML errors in journalctl logs: https://paste.opensuse.org/99027736
However, `/usr/lib/kscreenlocker_greet --testing` works as I'd expect.
Even `/usr/lib/kscreenlocker_greet` (without arguments) works and shows a proper lock screen.

As instructed in openSUSE's KDE channel, I also did `strace -fetrace=execve -p $(pidof ksmserver)`: https://paste.opensuse.org/78537251 (this output is from 1 lock attempt). Quoting fvogt: "The strace shows that execve succeeded, but at some point it fails with 127 (file not found)". I have no clue what could be missing…

As a workaround, I have disabled the lock screen completely for now.


STEPS TO REPRODUCE
1. Trigger the lock screen with a timer or a keyboard shortcut

OBSERVED RESULT
"The screen locker is broken and unlocking is not possible anymore. In order to unlock switch to a virtual terminal…"

EXPECTED RESULT
My lovely Breeze-themed lock screen, as usual.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Leap 15.3
KDE Plasma Version: 5.24.90
KDE Frameworks Version: 5.94.0
Qt Version: 5.15.2
Graphics Platform: X11
Graphics Processor: Mesa DRI Intel® UHD Graphics

ADDITIONAL INFORMATION