justflyingin

I am going to suggest something--take it or leave it.

I had a 7700 and now have an 8900.

Make sure when you are quilting that the thickness of the quilt doesn't bunch up and push the presser foot lever "up" slightly--not enough so that it doesn't sew, but enough so that it doesn't sew right. I have exactly what you described when the presser foot isn't 'hard' against the fabric. Of course, I didn't notice it at first. Only when I was done and looked underneath and saw exactly what you are describing-very loose and comes out just like a opening a feed bag.)

This would not happen on your samples as they are small. It happens when you have lots of fabric back behind the needle and bunching up and pushing the lever up.

So, my advice...check for that.

The solution...be very, very aware of how much thickness is backing up and pushing against the presser foot lever (the black thing). Keep pushing the quilt down and try to keep the thickness of the quilt flat in the area all around where you are sewing or where the presser foot lever might catch on it.