Created attachment 143226 [details]
Video of the bug

SUMMARY
If a KDE app starts up maximized, then you unmaximize the window, then you try to maximize the window, it won't let you maximize it( or if you unmaximize, maximize, then try to unmaximize) This does not apply to kirigami apps like discover.

STEPS TO REPRODUCE
1. Open an KDE app(like gwenview) that starts maximized(not kirigami apps though)
2. Unmaximize the KDE app
3. Try to maximize the KDE app
4. The KDE app will not maximize
5. If you can maximize the app, try unmaximizing it
6. Does not unmaximize

OBSERVED RESULT
The KDE app refuses to maximize or unmaximize

EXPECTED RESULT
They maximize and unmaximize normally 

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.23.2
KDE Frameworks Version: 5.87.0
Qt Version: 5.15.2
Kernel Version: 5.14.14-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × AMD Ryzen 5 3450U with Radeon Vega Mobile Gfx
Memory: 5.7 GiB of RAM
Graphics Processor: AMD Radeon™ Vega 8 Graphics

ADDITIONAL INFORMATION