Animate Editing - Spinning handles

So I was trying to go through the walk cycle tutorial from the Synfig wiki http://wiki.synfig.org/Doc:Walk_Cycle when this happened:

https://gfycat.com/FrenchYawningAtlanticridleyturtle

This happens occasionally. Why does this happen and is there a fix to this without having to edit each frame manually?

Hi! This happens because you can animate the tangents (yellow dots) too not just the vertex (orange dots) then if you invert its position, the animation is store, and you have that result. If you animate tangents just try to keep them on place and don’t twist his direction.