I'm sorry this happened to you! Thanks for the heads up!
As a pattern designer, I not only make the quilt myself but then I make it again after I have written the final hard copy. After that it goes out to five pattern testers before hitting the market.
Have you let Studio E know so they can fix it or take it down?
As for fixing it, have you considering using a strip of applique? It would straddle the long seam.