This is a first for me. As I was progressing and then rolling the quilt on the rollers this little nasty reared its head. ( you are looking at the backside of a quilt on the uptake roller after it has been quilted. The seam came apart, hello batting) I don't routinely check all of the seams of backings. Perhaps I should.
If you are a quilter who takes quilts to a longarmer here is a bit of advice.
I roll the quilts pretty tight when I am working on them. I pay attention to not put too much tension but there is still a good amount. So if the seams are not sound this can happen.
The person who made the quilt may have trimmed the seams too close, but more likely just wasn't paying attention to her seam allowance as she went along. It is okay to take more than 1/4 inch and press open on pieced backings.
Just wanted to share some info, things happen but if we take a few minutes to slow down and even correct booboos as they happen we won't forget about them later.
Happy quilting! I'm off to get our new puppy!