This is not a A321T nor 777-300. I did click on the link and it shows the leg available. ExpertFlyer also shows 3 upgrades available on this leg. So far everyone at AA says nothing is available, and yet it is a 321 showing 7+ seats in F available and 3 in C.
One agent indicated that maybe it's too far out to clear. But, this flight is a connection and the inbound cleared. AA.com still showing SWU available so there's a bug in their system somewhere.