This happened to me but only on FMQ. Talked to the Bernina rep about it and she said to change the needle. I did and still had the same problem. I kept trying different needles and finally ended up with size 80 and it worked just fine. Weird that everything goes fine with the walking foot and the same thread but a different needle. Hope I remember this the next time I FMQ, but its likey that I'll go through all this again.