Weird HiRes gui issue -- single VM bugged

So I run a qubes setup with 2 4k displays. This worked fine until yesterday, when I swapped around my screens (I have one in portrait and 1 in landscape mode). Since then, all VMs work fine except one, which doesn’t allow me to click anywhere in applications that I move to the second (portrait) screen. I have already configured the videoram buffer size (GUI troubleshooting | Qubes OS ), and for all other AppVMs I have no issues clicking in app windows on the second display.

Does anyone have a clue what might be causing this, and how I can resolve it?
restarting the AppVM, logging out/in, and even rebooting the host machine do not fix it.

running qubes 4.1, with KDE