I just called AA an booked and award JFK-NRT in F in September of this year on JL. The reservation is booked in "Z" but that shows up as Business when you pull up your reservation on AA.com. I called back and the agent said that while JL is in the process of updating its fare classes, some of them will not display properly but she assured me that the ticket was in F.

I'm guessing its currently in transition from JL to OW standards.