Walking animation in SC2

Usually a walking animation it starts with one foot backward that is brought forward, then the same thing for the other foot, and finally the animation is looped.
But when I look at the kriptor and cybranausaurus, their walking animation start from standing position, make one left foot step and return to standing position. Never is a foot brought from backward position to forward position.
However when you see those units in game, the walk normally, not one-stepping, standing,one-stepping, standing,....
So how do walking animations work in SC2?

EDIT:
Forget it, walking animations in SC2 work like everywhere else, it's just that I let some bugs in my sca importer.