You MUST make sure the film strips are completely dry before handling them and putting them in the sleeves. Having them dry to touch isn't actually good enough.... When films are not completely dry, emulsions (imaging surface) is actually very soft and will scratch very easily. If they are excessively high in moisture content (like yours), they will stick like that.

You can soak them in water and dry them overnight. DO NOT rub them with your microfiber cloth or anything else for that matter. You'll just damage that much more.

Really... dry overnight... it's the safest way.