I have no idea what's going on with the FBI, but my best guess is a benign explanation. I think they they didn't find anything worth prosecuting this summer. Then they found more e-mails. They figured they'd be damned if they sat on them and damned if they released them. They erred on the side of transparency. The Clinton campaigned had filed some FOIA requests on Trump and asked why are you releasing dirt on us but not Trump. So they expedited those FOIA requests. They used to tweet responses, but went to e-mail or other methods. Given how politically charged this is, though, they figured they'd tweet these recent things out. There's noting suspicious-looking about that, they naively thought. No matter what they did nearly half the people would be mad at them. They didn't realize how they would come off looking like a secretive agency responding to a shadowy conspiracy.