No, what your daughter is experiencing is UC in the retained cuff. This is easily treated with 5ASAs. Talk with her GI or surgeon.
Before I had my illeostomy, I was on a dairy free diet because of how sick it made me. After the surgery, I was really surprised to find out that I had LOTS of "mucusy stuff" coming out of my stump. If I avoid dairy, all dairy, then it is fine. Try to experiment with food. See what works.