Lots of speculation on Twitter about this—a failed attempt to re-open all closed subreddits and instate their own moderators. I can't imagine it'd be that, although I do enjoy the conspiracy, and more likely they were using the window of reduced traffic to make some larger changes and they went awry
A meme pointing out that u/spez was a mod of r/jailbait in 2008 was the top post on r/all a few hours ago
Doesn't seem that unbelievable when you look into some of the other stuff he's done. For example he secretly used his admin powers to edit user comments from users he didn't like or who criticized him.