I have seen similar things lately and it is not specific to a given flight.
The word from AA is that there are two 'versions' of the plane - 'business' and 'leisure'. Obviously the one with 12 F seats is 'business', but what I was told is that on some routes, over the longer time horizon, they are trying to figure out which 'version' is best. Hence, holding off on "publishing" the maps, despite them being available to agents and seats able to be selected.