SUMMARY
Using the Shift while moving a window does not recognize the Tile Manager split lines defined by Meta+T. Only the Quicktile options of half and quarter screen are shown (just like without the Shift)

STEPS TO REPRODUCE
1. define tile arrangement using the Tile Manager (Meta+T)
2. grab a window to move/tile and hold the Shift key
3. try to tile the window into one of the tiles defined in step 1.

OBSERVED RESULT
Window will only tile into the Quicktile locations (half and quarter screen locations) as if the Shift key were not pressed.

EXPECTED RESULT
Window should tile into one of the predefined tiles as configured under the Tile Manager Meta+T

SOFTWARE/OS VERSIONS
Operating System: Kubuntu 24.10
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.6.2
Kernel Version: 6.11.0-9-generic (64-bit)
Graphics Platform: X11
Processors: 28 × Intel® Core™ i7-14700K
Memory: 62.6 GiB of RAM
Graphics Processor: AMD Radeon RX 6800
Manufacturer: Micro-Star International Co., Ltd.
Product Name: MS-7D27
System Version: 1.0n: 

ADDITIONAL INFORMATION
dual monitory set up with Asus PA248QV as main and a Dell P2417H as secondary (in portrait orientation).
Tiling using the Shift key works as expected under wayland.

Also of note and may be related: using gddccontrol the Asus monitor shows up as a VESA standard monitor with no controls, while the Dell shows up as the correct model number (display port) even tho both monitors are connected via DP cables.