Created attachment 147260 [details]
Side-by-Side Screenshots Illustrating the Issue. Zoomed-In on the Left, Correct on the Right.

SUMMARY
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After rebooting my machine, the wallpaper is zoomed-in to the top-left corner of the image.
Modifying the scaling, position, etc. of the wallpaper does not take effect unless the "Display and Monitor -> Display Configuration -> Scale" setting is changed and reverted.


STEPS TO REPRODUCE
1. Set up the wallpaper & display settings (see "ADDITIONAL INFORMATION" below)
2. Shut down the computer, then reboot and log in.
3. Observe the desktop wallpaper.
4. Open "Desktop Settings -> Wallpaper"
5. Change the "Positioning" setting.
6. Open the "Display and Monitor -> Display Configuration" settings.
7. Change the "Scale" setting, and click "Revert" when prompted.
8. Observe the desktop wallpaper again.

OBSERVED RESULT
At step 3, the desktop wallpaper is zoomed-in to the top-left corner of the image.
At step 5, the "Positioning" setting does not have a noticeable effect on the wallpaper position or scale.
At step 8, the wallpaper looks the same as it did before rebooting.

EXPECTED RESULT
At step 3, the wallpaper should look the same as it did after step 1.
The other steps should not be necessary to fix the wallpaper appearance.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 35 Workstation
KDE Plasma Version: 5.24.2
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.2
Kernel Version: 5.16.11-200.fc35.x86_64

ADDITIONAL INFORMATION
Display Resolution: 2256x1504 (Native)
Display Scale: 150%
Wallpaper Layout: Desktop
Wallpaper Type: Image
Wallpaper Resolution: 1920x1080
Wallpaper Positioning: Scaled and Cropped