Rotation doesn't work with JointOrientation from kinect in Unity3D 5

A weird thing happen to my code, I don't know why I worked like this, but it did.

My code is like this:

             // Getting joint orientation data from kinect 
             // and construct it with Unity Quaternion
             Kinect.Vector4 targetRotaV4 = body.JointOrientations[jt].Orientation;
             Quaternion targetRotaQ = new Quaternion(targetRotaV4.X, targetRotaV4.Y, targetRotaV4.Z, targetRotaV4.W);
             Debug.Log("target rotation: " + targetRotaQ); // it did print something
 
             // Rotate the gameobject from its local rotation 
             // to the rotation I got from kinect
             jointObj.localRotation = Quaternion.RotateTowards(jointObj.localRotation, targetRotaQ, 45.0f);
             Debug.Log("Joint Object rotation: " + jointObj.localRotation); 
             // It did print value, too, not just (0, 0, 0, 0), 
             // but in the game, the gameobject didn't rotate, and the rotation didn't change in properties which kept 0
 
             // But!! When I ran the following code, it rotated! Everything looked good.
             /*
             Quaternion testRote = new Quaternion(0.1f, 0.1f, 0.1f, 0.1f);
             jointObj.localRotation = Quaternion.RotateTowards(jointObj.localRotation, testRote, 15);
             Debug.Log("Joint local rotation" + jointObj.localRotation);
             */

So my question is, why! Why the rotation couldn't work with my JointOrientation data from kinect which I did get the data because I print the value and it was not null or 0.

Plz help me out!