Machine is "gathering" stitches.
I am not sure why my Bernina 440 has started to "gather" my stitches. I just finished quilting a quilt using both FMQ and straight line with my walking foot, and had no problems. I went back to my normal setting of 4 on my upper tension, cleaned out the fuzz under the stitching plate, am using Aurifil in top and bobbin with a 90 needle (didn't change the needle from quilting). I was chain piecing today and the squares started gathering. My setting is at 2.4 (factory setting) and I don't know what to do to fix this. The internet was no help with this problem. Any ideas?