Desktop sometimes is squashed onto one monitor

Hello. I’ve had a very strange bug happen for a good while now and figured it was time to try do something about it. About 50% of the time I boot into my PC, the desktop is tiled wrong. I don’t just mean the images (although that does happen), but the entire intractable area on my screens gets miss-position. I can’t right click in the black areas, although the task bar works and so do applications running in that area.

Here’s what happens each time. The rock image is supposed to be on the right monitor and was got through the KDE wallpaper download tool. The image below that is supposed to be there and is a simple image I downloaded off the internet. The white area is space outside my monitors so no worries there.

I have no idea what changed to cause this and why it’s inconsistent. Only thing I can guess is it’s possible it started happening when I switched to that wallpaper, but it’s been long enough now that I have no memory of it at all.

Any help is much appreciated, thanks.

Edit: Important detail. This is on the X11 session. After having some problems with Wayland I figured I’d hold out a little longer to see if they get resolved first.