Created attachment 177196 [details]
Screenshot 3 showing cursor at roughly 80% size of what it seems to be intended to be

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SUMMARY

I attached various screenshots to a different ticket, all of them show Plasma 6.2.4 with the same cursor theme with the same cursor size setting with the same DPI setting, and yet the cursor size noticeable differs.

Screenshot 3 shows it at what seems to be around 80% of what the cursor size is meant to be.

Screenshot 4 shows it at what seems to be around 50% of what the cursor size is meant to be.

Screenshot 5 shows it at what seems to be the intended non-bugged cursor size.

Screenshot 6 shows the cursor theme used.

Those screenshots are all made with Plasma 6.2.4. Triggering the bug to vary the cursor size on the plasma taskbar seems to involve changing the DPI scale and cursor theme to something else, then changing it back, and if you do it in just in the "wrong kind of right order" then it'll result in a different cursor size. Also, Firefox just seems to like to get it very wrong as well, although I've seen it rarely use the correct cursor size but a wrong cursor image of a different theme.

STEPS TO REPRODUCE

1. Use a non-100% DPI size and a fixed size cursor theme (I think it's a 32x32 or 24x24 one)
2. Change DPI sizes a lot
3. Try various native Wayland applications like Firefox and hover the mouse around and observe the cursor size

OBSERVED RESULT

Cursor size varies a lot, and only sometimes seems to be what it's actually meant to be.

EXPECTED RESULT

Cursor size is stable.

SOFTWARE/OS VERSIONS

Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: postmarketOS v24.12 based on 3.21.0
KDE Plasma Version: 6.2.4
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.0

ADDITIONAL INFORMATION