OnTriggerEnter works once, OnTriggerExit not at all?

Hi I have the player controlling a cube with a box collider and rigdidbody. When the player mesh collides with the sheep mesh I get the message “Collision Detected” but when I leave the area of the sheep mesh I do not get the message “Left Collison”.

	void OnTriggerEnter(Collider other)
	{
		if(other.gameObject.tag == "sheep")
		Debug.Log ("Collision Detected");
	}
	void onTriggerExit(Collider other)
	{
		if(other.gameObject.tag == "sheep")
			Debug.Log ("Left Collison");
	}

The sheep objects have sphere colliders and sheep tags. Why is it not detecting when I have left the area of the sheep objects?

Indeed tanoshimi. Collisions works. We have overflow malfunction somedays. Ouch.