Created attachment 147679 [details]
A screenshot demonstrating the wrong position of the notification

SUMMARY
After a screen got unplugged while the machine is suspended, Plasma shows notifications in the wrong spot.


STEPS TO REPRODUCE
1. Have an external screen connected, with the internal screen being set up "to the right of" the external one
2. Put machine to sleep, unplug external screen, resume machine
3. Make a notification happen

OBSERVED RESULT

The notification shows in the wrong spot, it partially clips outside of the visible area and overlaps with the toolbar. (See attached screenshot.)

EXPECTED RESULT

The notification should show where it usually does: in the bottom right corner, *above* the toolbar.

SOFTWARE/OS VERSIONS
Operating System: Debian GNU/Linux
KDE Plasma Version: 5.24.3
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
Kernel Version: 5.16.0-4-amd64 (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Xeon® CPU E3-1505M v5 @ 2.80GHz
Memory: 31,2 GiB of RAM
Graphics Processor: Mesa Intel® HD Graphics P530

ADDITIONAL INFORMATION
This seems to be a zombie bug that came back: https://bugs.kde.org/show_bug.cgi?id=373379.
This is a regression, the same sequence of actions worked with before the latest KDE/Plasma update (previous I was on 5.22 or 5.23).

It's not just notifications, other things like KRunner also show in the wrong spot.

Connecting and disconnecting another external screen while the machine runs fixes the problem. So it seems like a bug was introduced recently where Plasma fails to notice screen geometry changes in some situations related to system suspend/resume.