My suggestion is, that you break down your process to see which step introduces the unevenness. If you do only the FD step and then fix right away, you have a (more or less) proper negative that you can enlarge, any unevenness from the FD step should show up right there. Bleach is a process that runs to completion and should not cause these problems. If you get proper negatives but your positives still show unevenness, in all likelihood you have issues in the second dev step.
One thing that worked wonders when I had unevenness was a stop bath after each dev step, or at least make the "pouring out" as fast as possible.