There are some numerical instabilities in the bezier part of Paths, which makes path stroking kind of "snap" in certain conditions. You can reproduce it by playing around with the Path Stroking demo, with the default settings.
1) Stop the animation
2) Set pen width to full
3) Move the bezier around till you get a sharp corner.
4) When playing with this "corner" you can see that it sometimes snaps in the stroke.