Originally Posted by
Tartan
I think it is Heather over on www.ankastreasures that refers to those as "bird's beak" corners. She says it is indeed from too much fabric in the corners. Make sure you stop sewing the width of the binding from your corner and when you fold it up and then down to go down the next side, make sure that the new fold is not above the sandwich edge. She has some good tutorials on binding at her site that might help.
Thanks Tartan! I thought this was her problem but I couldn't figure out how to word it!!