Bob Ducsay ?

I noticed when i saw the movie that Bob Ducsay's name was not in the credits. And Stephen Sommers made this movie and they had worked together in all the movies he had directed ever since Catch Me If You Can (1989) , The Adventures of Huck Finn , The Jungle Book (1994) , Deep Rising , The Mummy (1999) , The Mummy Returns , Van Helsing and G.I. Joe: The Rise of Cobra. I wonder what happen why he was not involved if maybe they had a falling out or something.