It's one of your addons dealing with KEYBIND_STRIP. Just do a search.
It need to be manipulated with a callback on the scene. If not, you can have errors like this.
Basically to avoid the error, it should be :
Lua Code:
THE_SCENE_WHICH_****_EVERYTHING:RegisterCallback("StateChange", function(oldState, newState)
if newState == SCENE_SHOWING then
KEYBIND_STRIP:AddKeybindButtonGroup(KeybindStripDescriptor)
elseif newState == SCENE_HIDDEN then
KEYBIND_STRIP:RemoveKeybindButtonGroup(KeybindStripDescriptor)
end
end)
Have fun searching.