It used to be that AP holders with resort stays had the exact same benefits for FPs as regular ticket holders. However, something has changed in the FP system. It works properly for AP holders on their first stays -- 60 days out w/a 14 day limit. But, if you have another stay that is within 60 days of that first stay your window WILL NOT open until you check out of your first stay. So, let's say you have a 5 day stay in early May and another stay in June, you WILL NOT be able to make ANY FPs for June until your May stay ends.
To confirm, are people seeing that the second stay does not open until the first stay ends even if you're under 7 days of FPs from the first stay (so, in your example, 5 days of FPs booked in May doesn't allow even 2 days of the June stay to open)? I have stays 27 days apart with FPs for my first stay opening in a few days, and I'm trying to figure out if not booking any FPs at all for that stay would allow my second stay to open on time or if just the fact that I have two stays close together linked to MDX is going to screw up the second window. I don't really NEED FPs for the first stay. I do need them for the second. Ugh.