I would give them a call, a friend had one that went like that, and she actually came to the local Baby Expo with me and they just replaced it there and then, no questions asked, and said that there was a problem with a batch delaminating.

I haven't had it happen to any of mine, but do keep a listen out incase it does.
That friend was me - I posted a while back about it too. Peppermint IBs!! I had a couple of others have issues too, and they swapped them over with no hassles either.

The fault is the batch of material where the laminate is coming away, and then it sticks to itself internally. It isn't a manufacturing fault - just their suppliers! I took photos of the nappies, and then sent them those and what I wanted to replace them with. They sent me the replacements and an envelope to send the faulty ones back. All quite easy really. I still love them and considering we pretty much use IB full time, I know it isn't all the nappies, just certain batches.