Nothing seems to be wrong with it.
I think what you're seeing in the first video is just the "wagon wheel effect".
The wagon-wheel effect is an optical illusion in which a spoked wheel appears to rotate differently from its true rotation. The wheel can appear to rotate more slowly than the true rotation, it can appear stationary, or it can appear to rotate in the opposite direction from the true rotation.
The actual positions of the bones is clearer if you don't select any bones and show all the the bone names.
Note that if you move the path constraint position from 0.0f
to 1.0f
(0% to 100%). That corresponds to one full lap around the path in the direction the path is defined.
If we assume your "MoveForwardRailPath" is called per update at 60fps, it would result in the path moving at:
.1% to 2% of the path per frame, or 6% to 120% of the path per second. Given the number of bones on your path, that does reliably result in a wagonwheel-like effect when inspected this way.
It seems to line up with the values you are seeing in the Skeleton Debug window.