That's really weird. Ctrl+C & V is used extremely often, but no other users have reported this. And Listary won't show up if a key other than Ctrl (e.g. C or V) has been pressed. Can you provide the detailed keystroke sequences you tried? For example, press Ctrl, press C, release C, release Ctrl, etc.
Make sure the hotkey is not taken by Windows. I don't have any trouble setting it to something like Win+C