I was attempting to book a ticket on NH with a TA based in Korea the other day, and although a particular flight had availability in the class (Y) I needed it, the TA told me that he could not book that particular flight. The reason he gave was that (paraphrased) "due to yield control by this airline, even though there may be seats available when seen from Japan [I was using EF but am located in Japan] where the fare is higher, there are none available in Korea where the fare is lower." (FWIW, this was a private fare so the fare rules are not available.)

This explanation makes no sense to me -- availability is availability is availability, no? If there is Y4 on a flight, and unless there are geographic ticketing restrictions of some kind, it shouldn't matter where one is when checking availability, I would have thought.