PUL Delaminating--is it from my dryer?

Ready2006

We run our pocket diapers through the dryer (always on low heat). Our dryer doesn't run hot at all--they're still pretty damp after a full cycle. We typically run it another 10-20 minutes after to get the dry (and even then, they're not bone dry).

So....a couple of my diapers came out of the dryer with the PUL delaminated. I'm wondering what I did wrong? We exclusively use Rockin' Green, and I've never used bleach (which I've read can cause this).