User blog comment:Crazylittlefreakgirl/Fairy Tail Official Pairings?/@comment-76.161.172.226-20120816145901/@comment-76.161.172.226-20120816194620

Thanks, though it didn't really take that much searching. This stuff seemed to be coming from facebook/tumblr, and a little searching turned up a tumblr post that linked one of the mangafox posts and called it a rumor. Then it was just looking around a bit on the thread.

The funny part of all this is that since this was initially posted Mashima got a twitter account, and in the course of the filler, one of the Japanese fans asked him about his role in the filler. Google translate mangles the exchange, but the gist is clear. Namely that it's the story Mashima wants, but the actual writing is done by the anime staff.

So basically Mashima himself has said he isn't writing the filler, but this still circulates.