Just another two thoughts. Have you tried using a larger needle.....with all the tight turns maybe you are getting some needle flex which may make the alignment of the needle and bobbin thread slightly off causing a next or loop. This was happening to me when my timing was just slightly off on my sit down machine....when my needle flexed just a bit...it caused a mess...took a long time for the tech to figure out my timing needed an ever so slight adjustment....while my problem was related to my timing....needle flex could also cause this so try a slightly larger needle and as it is stiffer, it may not flex as much...I don't really know just a suggestion. Also, as you have to move your frame on an uneven floor..check and make sure that the distance between the quilt top and the backing and also between the machine and the quilt top is consistant. I think the avante has a leveler bar so it should be consistent but perhaps if one leg is sitting lower it can be off.....I used to have a midarm machine where when I advanced the quilt, the quilt sandwich would tilt as more quilt accumulated on the take-up bar.....and if I did not properly manually level the top after each time I advanced the quilt, it made a mess with loops and nests as I approached the far side of the quilt top because of the increased distance. Sure glad I got my APQS Lucey, few problems over-all the solve...