This bug persists since quite a while, at least Plasma 6 period.

When using my laptop for a day or longer, mostly in idle, the panel stops reacting.
- krunner does not start with the META shortcut I defined
- I can hover the "icons only taskbar" icons and launch apps, but existing windows will not be displayed. I will not switch to an open window but always create new instances of the app
- Systray icons will work (minimize and open apps when clicking for example)
- an additional autohide panel appears when hovering
- other panel elements work fine too
- META+W, touchpad gestures and Alt+TAB work for switching applications
- hovering over the pinned app icons changes their color as expected
- right clicking the app icon shows the context menu including desktop entry actions like "open a private window" for firefox

When I restart plasmashell with systemd --user, the panel disappears and reappears but the icons-only-taskbar still does not update

I was not able to find relevant logs in journalctl, no errors when restarting plasmashell service either.

This issue is fixed after a reboot and seems to appear when I have my laptop on for a 2 days or so

My current
Operating System: NixOS 25.11
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.0
Kernel Version: 6.12.58 (64-bit)
Graphics Platform: Wayland
Processors: 8 × 11th Gen Intel® Core™ i7-1165G7 @ 2.80GHz
Memory: 32 GiB of RAM (31.2 GiB usable)
Graphics Processor: Intel® Iris® Xe Graphics