Alright, I've been chillen in #fw most of the day so here is the dealio:
It IS an AP25 issue, AP 25 was present on what is now known as the "deadly three" well before hand, and Microsoft decided to activate the check in this title update.
They are working on it and you should expect news in a day or two
This will be solved the new AP25 patches will have to be applied with abgx, possibly manually, and you're going to have to reburn. It is what it is.
This could happen again, it's unknown exactly how many dormant titles there are. The first known one is Fifa '08, but its not known if AP25 is on all titles released after that or just some. Either way, not a large issue.
UPDATE:
k3rn3l just came into the irc and described the situation in one word "problems"
when asked if it was AP25, he only said "yes and no"
make what you will of it, he said work would begin in the morning and that was the end of it