I like the "best behavior" theory or, as an alternate, a combo of diligence by the janitors; good behavior (except by spammers); and an usual configuration of the planets, sun, moon and Hurricane Katia has led to a situation where all considerations satisfied the requirements for automated reaping or the constraints of janitorial guidelines (permitting the aforementioned 'diligence' in removing cobwebs, etc.).

But, nonetheless, I suspect some glitch.