Allen,(posted 8781 days ago)You don't say what film/developer combination you are using, or what developer time. These could be critical to isolating the problem. If you are using short developing times (less than 5 minutes) the problem could be that this if where the developer first hits the film. The short times do not allow the other densities to catch up.
Is it possible that this is a light leak problem on your camera or tank?