Sometimes if I do not be careful to start and finish the seam at the 1/4" mark, that happens. When cutting, sometimes they are not all correct. I found that putting the paper template on a good strong piece of board or plastic helped keep my template accurate, then I drew my lines then used a ruler to add for cutting accuracy. Extra steps, but took care of any extra waive or short. Best Press is good for being sure that all is "pressed", not ironed. Not sure if this helps, but all the tidbits add for a better time making them.