On https://2019.www.torproject.org/docs/onion-services it says that whenever the client or server contacts the rendezvous point or one introduction point, it always builds a full tor circuit.
So, why does it say (near the ending) that
In general, the complete connection between client and onion service consists of 6 relays: 3 of them were picked by the client with the third being the rendezvous point and the other 3 were picked by the onion service.
It implies a circuit of 2 relays from the client to the RP. Maybe the client builds a full circuit to the RP only at the beginning (to share the one-time-secret) and then later uses it as third node?