In the lastest 1.8.0.13 Beta, i spawned the Skeleton and the animation doesn't render correctly. Like the skeleton doesn't move its arms and has a weird walking animation. It also happens to some of the entities.
Like the geometry model 'LeftArm' doesn't specified to be move or animated. Maybe the MoLang integration has been updated? Or the models has a problem when binding them with animations?

 
I hope this will be fixed in the lastest beta soon.

I can't post the .gif image yet, soon.