Brave has had a somewhat troubled development, so this isn't that surprising.
Crazy rumors floating into our offices this afternoon from reliable sources. We hear that Brenda Chapman, the first woman director at Pixar, has left the studio and is no longer directing Brave (previously titled The Bear and the Bow). We hear that she was pushed aside from full directing duties a while back, and that story artist Mark Andrews (who also co-directed the Pixar short One Man Band) has taken over directorial duties. We understand that the change officially happened last week, although it had been inevitable for some time.As mentioned in the article, directors being replaced on animated films is a fairly common occurrence. But this is particularly noteworthy because Brave was to be the first Pixar film directed by a woman.