SUMMARY Switching keyboard layouts stopped working completely on X11. STEPS TO REPRODUCE 1. Add secondary keyboard language layout (in my case i use US and RU). 2. Try to switch it via hotkey or system tray applet. OBSERVED RESULT US layout remains unchanged, only way to switch is to manually do it via setxkbmap. EXPECTED RESULT Switch to another layout. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Arch Linux, Kernel: 5.11.9-arch1-1, KDE Plasma Version: Plasma 5.21.3 KDE Frameworks Version: 5.80.0 Qt Version: 5.15.2 ADDITIONAL INFORMATION Switching keyboard layouts does work in Plasma Wayland session, any other DE/WM like Gnome(both X11 and Wayland), i3wm, awesomewm, XFCE. It doesn't work anymore in Plasma X11 session exclusively. Tried full reinstall, switching users, etc - nothing fixes this behaviour. This bug breaks workflow in Plasma X11 session completely for multi-language users.
Started to work again after manually removing all kde and plasma config files from ~/.config.