Every time the subject of mistakes in quilts comes up, so does the old folktale of the Amish leaving a mistake in every quilt. I think it's just that... a folk tale. The Amish are great craftspeople who do the best work in everything they touch. I can't see them leaving something like this front and center on a quilt, just to appear humble. And I doubt the piecer of this quilt did, either.
I don't think I'd ever be able to use a longarmer a second time if they quilted over an obvious mistake without at least asking if it was meant to be there. Did the longarmer even LOOK at the quilt, or just set the computer program and let it go?