Armature freezes problem (BUG?)

I am making a game where the player is using a sword to kill enemies, but I have some issues with the combat-system.

When the player is attacking:

The sword and the blue plane is touching the red object, the armature is supposed to play an action to pull the sword out. This works well the first hit as you can see in the video. Although the second time the armature is acting weird and starts to freeze.

What is causing this, and how can I fix it?

there are issues with blending actions currently, try using 2.75 I believe*

I can usually only get 1 or 2 actions to blend (action+idle) without locking up.

I am only using one layer.
I tested without blending between the actions and it sadly turned out being the same.

you should never play 2 animations on the same layer, unless they are to be blended* I think****