Not a bug. Well, not exactly. There IS a bug on the forums that was granting the winners of the Free Kingdom Event access to the 10k forum even though they didn't have 10k IP.
Realizing they had access, many started exporting and caching all of the threads and images.
To prevent this until I have time to fix it, I've temporarily disabled the Exclusive Access forum.
The Exclusive Access forum will return tomorrow.