So far I have only used my Juki 2010 for straight stitching. Want to learn free motion quilting but too many other projects in line first. I was watching a video this evening where Rob at Man Sewing is giving great, free lessons online. Tonight he mentioned just what you describe. He showed how it acts and he said often you will be using the free motion foot and forget to drop the presser foot and that's what happens. He said with the free motion foot it is very hard to tell if it is up or down, especially where the quilt is thick. He said it can cause you to go nuts trying to find the problem. He says to remember to always check that the presser foot is down. Said it has happened to him and he has been free motion quilting for years.