I used to have that problem once in a while it rears its ugly head now. I started adjusting my sewing....for example if most of the seams were pointing towards the feedogs I simply flipped it and sew in up side down after I pin. I also look as the seams approach the foot and double check they are laying flat. I can't stand ripping and resewing but will do it every time because that is one of the things that bothers me in my projects so I try to avoid that. Now if when going over that seam if my stitch length would stay consistent I would love that!! Sometimes it goes long....sigh...