I had something very similar happen as well, and I’m on AMD and only 2 monitors.
I have not been able to update for a couple of weeks due to craziness at work, so the last time I had updated before today was mid July. I normally ride the testing branch, but during diag of what I was seeing I was having problems on both the Testing branch and the Stable branch.
I performed a full system update today, and upon rebooting and logging into through SDDM my desktop was… interesting. I’ll try and describe as best as possible as it was very strange what was happening.
I have 2 monitors, a 3440x1440 and a 2560x1440. The first one is my main monitor. On this monitor I saw 2 desktop backgrounds split 50/50 on the screen. If I click on either the other would go away. The 2nd monitor had no background, just black. The interesting thing is that the mouse would go to the second monitor but right-clicking on the desktop or clicking and dragging (to create a selection box) did nothing. I also have 2 panels, 1 on each screen, and they were working like normal.
The other thing I noticed was that my themes were not being applied to windows, and bringing up krunner would freeze all keyboard input for about 30 seconds. Also many graphical elements were missing (like the pin button on krunner, etc.).
I tried rebooting and same issues. I attempted to look at Ksystemlog to see about log errors and there were many QT drawing errors and bad calls. (I didn’t happen to grab any at this time)
I have TimeShift on my system using btrfs, so I restored back to pre-update and the system was running fine. This is when I went from Testing>Stable to see if there was an issue in Testing. The exact same issue happened after a system update in stable.
After Timeshifting back to pre-updates, I started searching forums, etc. This is the only thread I really found and there didn’t seem to be any KDE support tickets open for anything like this. So then to try and troubleshoot I was looking to see what packages are being updated that could cause this.
That’s when I noticed that manjaro-kde-settings was being updated with the system and this was the only “KDE” specific update. I added this to the IgnorePKG in pacman config, and updated the system. Upon reboot everything is working fine.
It appears there is something in manjaro-kde-settings that is causing this issue, at least for me.
The version I’m currently on: 20200804-1
The version that my system was updating to: 20210812-1
I’ve been running about an hour from the update with the ignore on this package and running smooth so far.
