Always to be sure to check the tension off to the side of the quilt before you begin. As longarmers we always ask for 3-4 inches extra backing and batting on each side. I tell my customers I own this fabric. This is where I test my tension after every bobbin change. I won't quilt the body of the quilt until I am satisfied off to the side. It looks like the top tension was to loose and and the bobbin thread pulled it down. PM me if you need someone to quilt this, I would be happy to discuss this with you.