So then, perhaps it is the fusible issue that DHMom described!


More wonderings again ...
... perhaps fusible deteriorates with age?
...... perhaps fold lines compromises it?
......... perhaps why some of the webbing comes off with the backing?

Most all iron ons require that you do not use fabric softner or dryer sheets as well as you have to prewash to get chemicals the vinegar will ensure there are no chemicals in your fabric

I use steam a seam alot, and I never pre wash my fabric. Make sure you let your fabric cool down after fusing it, before you try to peel the paper off.