cannot pass the same transit point more than twice in a roundtrip/multicity journey.
JFK-HND(or NRT)-CTS-NRT-HKG-NRT-JFK violates this.
JFK-HND(or NRT) -KIX-HKG-NRT-JFK doesnt (passes through HND/NRT only twice)
This is to avoid a "round trip within a round trip" type of illegal booking (that would essentially be two separate tickets trying to be booked as one ticket.
Read up more here.
https://www.ana.co.jp/en/jp/amc/refe...d/tk/zone.html