The AO3 adult verification issue has been affecting me consistently for the past few hours on every fic I try to update. I checked the AO3 changelogs (
http://archiveofourown.org/admin_posts?tag=1) and it looks like they updated a myriad of things on June 15. Maybe one of those changes (e.g. switching from XHTML to HTML5) is just now being implemented across the board and it's affecting FFF communications with the AO3 servers?