Most likely they weren't stretched enough during the process. I'd say something to her first. See if she offers to fix the problem (probably will). If not, I'd be happy to take a look at this for you. My business is taking a turn toward finishing services and I'm good at binding.
Within the last 6 months, I had a long arm quilter with an excellent reputation quilt 2 queen size quilts for me. The workmanship on the quilting is beautiful. However, I had her attach the binding on both quilts. I am very disappointed in the binding. It is very "wavy" when hanging or on the bed. I've done binding on many quilts completed on my domestic machne and have not had this problem.
Any suggestions on how to fix or will I just have to live with it? It appears perhaps the borders were stretched during the quilting process. I paid a great deal of money for something I am not satisfied with.