MQTT status request fails (f.e. nuki/ID/state)

Hi all, using NodeRed I want to enable a smart button that changes it behavior according to the state of a certain lock. So, when the button gets hit, I wish to request the state of a lock. I send nuki/ID/state with empty payload. The result is, that the state node gets lost in the response. Btw, same happens for all other topics I could ask a status of. My expecation is, the the lock answers by sending the current state as a response. It does not do. Any idea?