Projector Position Wont Move (Attached to Parent)

I've parented a Projector to an object that moves(rigidbody) but it will not update its transform when the parent moves.

I have even attached a script and used the parent as a reference to assign the transform position directly and it still will not move.

I am using the latest Free version.

I've found a solution although I don't know why parenting didn't work like everything else?

Instead I've written a Shadow script that I attach to the object which has a public transform field called shadow.

The projector is assigned to the shadow field.

public class Shadow : MonoBehaviour

{

public Transform shadow;
public float yOffset;

void Update()
{
    shadow.transform.position = new Vector3(transform.position.x, transform.position.y + yOffset, transform.position.z);
}

}