Try rebinding the key and restarting. If not, Idk what to say.

You'll need to navigate to: and delete
Binding and unbinding commands is not possible through Lua since it can be exploited by an addon to do nasty things like erasing a user's keybinds, so to allow these keys to be assigned from the gmDoom menu this addon has its own basic bind system, which is why the normal unbind commands would not have any effect.