Created attachment 158454 [details]
Screenshot taken from a still from obs recording

STEPS TO REPRODUCE
1. Set both monitors to 125% scaling
2. Open spectacle
3. Click "rectangular region"


EXPECTED RESULT
All monitor output becomes static (except spectacle overlay) in order to select a rectangular region for the screenshot.


OBSERVED RESULT
Primary horizontal monitor's image becomes static and overlayed on top of itself at a smaller scale. Selecting a rectangular region works as expected as if the bug was not apparent. Which is to say, I'd have to remember the outline of the content I want to snip and blindly do so. No artifacts in the result. 

Using the attachment as reference:
The part of the desktop that's smaller is the static image. The part of the desktop that showing outside is my actual desktop still rendering in real time. I know this because I have a live wallpaper on my main activity, and during the rectangular region selection process, the live wallpaper is still moving in the background. 


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch
KDE Plasma Version: 5.27.4
KDE Frameworks Version: 5.105.0
Qt Version: 5.15.9
Spectacle: 23.04.0


ADDITIONAL INFORMATION
CPU: 7950x3d
GPU: Nvidia GTX 1080 
- Both monitors are 4k, and attached to my gpu. My left monitor is vertical but the bug seems to persist when horizontal also. 
- Secondary vertical monitor has no issue. I was able to swap this bug on either monitor, but I don't know how to reproduce. Bug present on one monitor at a time. 
- This happens on both X11 and Wayland. 
- This doesn't happen when both monitors are set to 100% scaling. 
- I was able to get a screenshot of the bug using obs screen recording.  

The only related logs I can see from journalctl is:
kstart5[5244]: Omitting both --window and --windowclass arguments is not recommended
systemd[1980]: Started Spectacle - Screenshot Capture Utility.
spectacle[5251]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()
spectacle[5251]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()
spectacle[5251]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()
spectacle[5251]: qt.qpa.wayland: Wayland does not support QWindow::requestActivate()