Looks like it might have gotten fogged. This usually happens when you're loading it in the reel. How light-tight is the space you're loading your film? It's critical that it's completely light tight for film.

The next potential trouble area is agitation. Are you agitating consistently when you're developing? If you don't you could end up with one part of the film not getting developed as well as another. My guess is still fogging when you're loading. But check your agitation, too.