Created attachment 145076 [details]
A screenshot showing the window rules' settings that cause the issue

SUMMARY
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I have setup "Window Rules" so that some of my apps are "restricted" to a specific virtual desktop, eg. Firefox to Virtual Desktop 3 (screenshot attached).
Under X11, if I am on Virtual Desktop 1, and launch firefox, all firefox windows are launched in Virtual Desktop 3, which is reflected on the pager panel widget. This is the expected behavior. Doing so under wayland, however, results in firefox windows launching on Virtual Desktop 3, but a "ghost" window also appearing on the virtual desktop I have launched it from. Moving the "ghost" window in the pager to a different Virtual Desktop results in moving the actual window there. A  "ghost" window remains on the pager where the actual window actually was. Moving the actual window using the pager does not remove the "ghost" window.
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STEPS TO REPRODUCE
1. Create multiple Virtual Desktops and activate the pager widget
2. Set window rules as in the attached screenshot
3. Log in using a wayland session
4. Launch firefox from Virtual Desktop 1
5. Watch how the pager widget makes firefox show up on both Virtual Desktops, even though the window only exists on Virtual Desktop 3
6. This does not occur under X11

OBSERVED RESULT
When window rules are active under a wayland session, the pager makes copies of windows on the wrong virtual desktops

EXPECTED RESULT
The pager widget displays the windows only on the desktop they currently exist in, just like in a X11 session.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
KDE Plasma Version: 5.23.4
KDE Frameworks Version: 5.89.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
I can reproduce the issue on two independent systems