Did you ask one of the staff in the arrival hall? Wondering if it was a courtesy from the staff or a rule similar to Global Entry.

When I arrived HND T2 internationally for the first time, I asked if there is an e-gate for TTP. The staff guiding passengers told me the e-gates were for Japanese only and told me to line up with other foreign passport holders. Afterward since the lines were never long, I never bothered to ask again. But given the increasing arrivals at T2, would be great if priority lane is an option.