Uneven stain along one edge is an agitation problem in my experience. If you are using a tank, try more solution (I had this problem at first in my Nikor inversion tank, and increasing from 1000ml to 1200ml solved it). If you are using trays, try a bigger developer tray and try to keep the film in the middle of the tray. For tray development I use an 8x10" developer tray for 4x5" sheets (having experienced darkening of edges with 6x8" trays, but I do use the 6x8" trays for the rinse and fix).