Bug 458028

SUMMARY
Task bar moves half a screen to the right when using independent dual monitors and powering then off then on.

STEPS TO REPRODUCE
1. Dual monitor setup with 2 separate displays left display 0 rotation (landscape) right display rotated (portrait).
Task bar at the bottom of the screen. Everything else set to the default plasma configuration.
2. One display using HDMI the other using Thunderbolt.
3. Task bar located at the bottom of the landscape display.
4. Power both monitors off, then power them back on (sometimes even this isn't necessary to provoke the bug).

OBSERVED RESULT
The task bar on the landscape display is shifted 1/2 a screen to the right and appears part way up the right hand (portrait) display on the right. To return the task bar to its correct position you have to enter edit mode and drag it back to the left hand display.

EXPECTED RESULT
The task bar remains where it was after power cycling displays that are configured as separate displays.

Operating System: Arch Linux
KDE Plasma Version: 5.25.4
KDE Frameworks Version: 5.97.0
Qt Version: 5.15.5
Kernel Version: 5.15.61-1-lts (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i5-8259U CPU @ 2.30GHz
Memory: 31.2 GiB of RAM
Graphics Processor: Mesa Intel® Iris® Plus Graphics 655
Manufacturer: Intel(R) Client Systems
Product Name: NUC8i5BEH
System Version: J72747-308

ADDITIONAL INFORMATION
Easily recreated.