Created attachment 166520 [details]
Bad icon

SUMMARY
***
System tray icon for Notifications has turned into an anonymous icon with a ? instead of a themed icon. This happened after an update to Plasma 6.0.0 on an up to date Neon, using all default theming (Breeze, Breeze icons), and persists when you switch to a different icon theme. It persists after reboot and logout.
***

STEPS TO REPRODUCE
1. Update Plasma to 6.0.0 

OBSERVED RESULT

Notifications applet icon is just a rectangle with ? in it, and not the right size for the system tray.

EXPECTED RESULT

Notifications applet icon is themed properly.

Operating System: KDE neon 6.0
KDE Plasma Version: 6.0.0
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.5.0-21-generic (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-10510U CPU @ 1.80GHz
Memory: 46.7 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics
Manufacturer: LENOVO
Product Name: 20RYS0M100
System Version: ThinkPad T490

ADDITIONAL INFORMATION

This worked before 6.0.0