It is not a firm law that everything must be pressed to the dark. It is a good rule to try to live by mostly because it a good habit and it has less chance for the seam to show through. But, sometimes it doesn't work that way. In the same way that sometimes they don't nest and sometimes they twist. When this happens, the problem is the bulk when quilting. But, if it only happens a bit, or you press really well, it isn't too difficult and no one will see it. We are are own worst critics!