Do you use ibus input methods only?
In my case, I wanted to keep my configured xkb keyboard layouts + I wanted to be able to use ibus in parallel for CJK.
Ok, there must be a problem with *my* KDE setup: when I try to disable KDE keyboard layouts, KDE does not persist changes to the next session: when I log in next time, KDE keyboard layouts are enabled again and interfere with ibus.
