Yeah, sounds like speed is the culprit!

It's hard to go slow on curves, I have the same problem and I get the same thing you describe. I'm still working on getting into the habit of pushing the pedal down a little further when I'm looping around and trying to keep a slower speed the rest of the time...getting better but not quite there yet!

I think it's like any other skill - practice, practice, practice! I was afraid to begin FMQ because it probably wouldn't look good at first, but I decided I just needed to begin. The first quilt I had a lot of huge stitches because I was going too fast, but I'm improving! And I did take my Bernina FMQ attachment in to have it reprogrammed, and that helped as well. Good luck!