That means youbare doing one of or any combo of the following... pushing too hard, holdng the angle steeper than you need or using too flexible of strop. My best strop is 1/8 thick leather glued to a wooden board
I now use a 2x4 under my strop. I think I was pushing to hard or not holding the edge angle right.
Im practicing a very light touch on my angled edges now so far so good lately. But Im not confident at stropping edges yet.