Turn off fcitx when you go back normal mode.
If you want, restore fcitx state when you re-enter insert mode.
clone this repository, symlink fcitx.kak to your autoload directory.
write setup-fcitx-fcitx-switch or setup-fcitx-auto-off in your kakrc.
setup-fcitx-auto-off do only turn off.
setup-fcitx-auto-switch do both turn off and restore.