SUMMARY

Right clicking in e.g. konsole makes the right click menu show up near the screen edge instead of at the cursor location. 
- This appears to occur for a lot of KDE applications, but not for GTK applications, some Qt applications appear unaffected as well (e.g. SciDaVis)
- Launching e.g. konsole with QT_QPA_PLATFORM=xcb fixes the issue.
- The right click menus of the desktop/plasmashell are not effected, nor the right click menu's of the window title bar. This only occurs when right clicking *inside* the application. (e.g. right click the konsole titlebar: normal, right click inside the konsole window: menu is all the way on the edge of the screen)
- It only occurs in wayland
- It only occurs on my PC which is using the iGPU multi-monitor feature (i.a.w. the output ports of the integrated Intel GPU are used as well as the output ports of the dedicated GPU). It does not occur on my laptop which has only the Intel GPU.


STEPS TO REPRODUCE
1. Start wayland session on a computer with iGPU multi monitor enabled
2. Start any KDE application (e.g. konsole, dolphin, kile, kate)
3. Right click anywhere inside the appliction

OBSERVED RESULT
The right click menu pops up on the right edge of the active monitor


EXPECTED RESULT
The right click menu pops up at the cursor position, as it does for all other applications.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 5.12.6
(available in About System)
KDE Plasma Version:  5.22.0
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2