Irish Dance Outfit of Today (RETIRED)

I have two sets of Nellie's Irish Dance Outfit. One of them was bought directly from AG. The other was bought recently at a thrift store, and didn't include the girl sized headband. So, I have two doll sized headbands and one girl sized headband between the two outfits. All three of the Irish Dance Outfit headbands have developed discoloration on the fabric. They have developed rusty-brown marks that range from streaks to tiny freckle-like dots. The two doll sized headbands have these marks only on the side of the fabric that faces the doll, so they don't show on the velvety front. On the girl sized headband, the marks are on the velvety front of the headband as well as the inside. I don't believe this is an isolated incident, because the headbands from the outfit I got new from AG and the secondhand one both have the same type of discoloration. I suspect the discoloration is something similar to what happens to Samantha's Spring Party dress. Maybe there was some kind of glue used in it? I checked both of my Irish Dance dresses, and they do not have the discoloring. Just the headbands. You really can't see the discoloration when the doll is wearing the headband, so it isn't too much of a problem for me as it is now (hopefully it won't progress further), but I just wanted give everyone a heads up about this, and see if anyone else is having the same problem with their headbands.

Thanks!