Could it have something to do with Apple's event?
(I know that correlation does not imply causation, but still)
I doubt it. Apple is popular, but not
that popular. Especially enough to bring down a platform ran by Microsoft.
I'm guessing it probably has something to do with upping the security. They've seeing a huge surge is account hacks, malicious bots, and CP being uploaded to servers and reported en masse. They won't admit it, and probably never will. Just an assumption, though.