Created attachment 164394 [details]
top bar layout to recreate the issue. Also happens with a clean top bar with only 'Global Menu'

SUMMARY
The layout that I am using is fairly peculiar. It basically amounts to a vertically flipped macOS layout with the global menu on the right side of a topbar. This mostly works as expected except that when accessing a sub drop down from within a drop down from the global menu, on first hover it doesn't detect the edge of the screen it gets displayed on the right side. Meaning the sub drop-down gets cutoff by the screen. However when I hover over the same option again in the drop down it will detect the edge of the screen and display on the left side like it should.

This is recreated on both plasma 5 and 6's most recent releases. Also on both wayland and X11

STEPS TO REPRODUCE
1. Have a layout as shown in the provided image with a bar that has the 'Global Menu' on the right side of the screen.
2. Open a program that supports the 'Global Menu' for example 'Kate'
3. Once open find a drop down from the Global menu that has an arrow pointing to the right of it indicating a sub-menu. 
4. Hover over it. A sub-menu should now appear to the right side of the hovered over menu item. If the drop down is close enough to the edge and/or if the menu sub-menu is sufficiently big enough it should fall off the monitor.
5. Stop hovering over the menu item periodically to disappear the sub-menu. Hover back over it again to make it reappear. It should now appear on the left side of the drop down. This also works when keeping the application using the global menu in focus and leaving the drop down entirely and going back to the same menu item again.

OBSERVED RESULT
On First hover the sub menu appears on the right, falling off of the screen.
On Second hover of the same menu item it appears on the left as it should.

EXPECTED RESULT
The sub menu of the drop down from the 'Global Menu' should appear on the left of the drop down on first hover.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 5.27.10
KDE Frameworks Version: 5.113.0
Qt Version: 5.15.11
Kernel Version: 6.6.7-arch1-1 (64-bit)
Graphics Platform: X11
System Version: -CF

OTHER OS
Operating System: Arch Linux 
KDE Plasma Version: 5.91.0
KDE Frameworks Version: Cant check bc system setting is broken(Ill file a bug report for that).
Qt Version: 6.6.1
Kernel Version: 6.6.8-arch1-1 (64-bit)
Graphics Platform: Wayland
System Version: -CF