SUMMARY
***
NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***
I have a computer with two displays. 
When i resume the computer from sleep or hibernate, one display (the bigger 4k one with 125% scaling) stays completely black, the other smaller one (1080p no scaling) surprisingly shows whatever was shown when the computer was put into sleep.

This happens almost every time when i put the computer into sleep or hibernate, so it's more or less reproducible.
It is not only extremely annoying but also kind of a security risk, since everybody can now see, what i've done before i put the computer into standby.

I am not sure, if the category that I selected is the correct one, so please move it accordingly.
I am using Plasma 5.25 on Manjaro Linux.

If I can provide you some additional debug information, I would be happy to help.

STEPS TO REPRODUCE
1. Put the PC into sleep or standby
2. Resume it after a while
3. 

OBSERVED RESULT
One display stays completely black and reports after a few seconds that it's not connected.
The other one shows whatever was shown before it was put into standby.

EXPECTED RESULT
The lock screen should be shown.

SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux
KDE Plasma Version: 5.25.5
KDE Frameworks Version: 5.97.0
Qt Version: 5.15.5
Kernel Version: 5.15.65-1-MANJARO (64-bit)
Graphics Platform: Wayland
Processors: 6 × Intel® Core™ i5-8600K CPU @ 3.60GHz
Memory: 31.3 GiB of RAM
Graphics Processor: AMD Radeon RX 6800
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7B46
System Version: 1.0

ADDITIONAL INFORMATION