In my experience, severely wrinkled fabric after the quilt is completed is usually a sign that it was not quilted enough. Just because your batting says you can go 10" between quilting lines doesn't mean you should.
When you wrote "koni" I am assuming you meant Kona fabric which is Robert Kaufmanns line of solids. Solid fabric will show the wrinkling a lot more than a print because there is nothing to camouflage the shadows and highlights caused by the peaks and valleys of the wrinkling. Just like quilting will show up a lot more on a solid than it does a print.
You can try re-washing the quilt or wetting the offending area and then blocking your quilt and let it dry flat. Then I would go back and put some more quilting (probably a lot more quilting) in or this will be a problem the life of the quilt.