We had the shoes the same construction (different color) and also initially the same problems. Therefore, we have the simple (in my view completely unnecessary) material cut off, as far as possible at the seam. Has no negative effects, nothing fray, going to o. Ä.! The zipper difficulties have done himself. First, they are smoother, as well as our son found very quickly the hang of how it hinbekommt it. They were with us for all time favorite shoe - also because of good quality - we had then bought the the next size again.
However, one must know that the shoes SMALL precipitate as usual!