Why is my camera sticking and showing lag while using iTween to follow a rigidbody-actor?

I have a little sidescrolling camera powered by iTween, very simple in it’s scripting - however I’ve noticed that once I actually start my character, the camera “sticks” in place for five-ten seconds before snapping to and following the character. The character is being moved through physics with a velocity-powered launch.

using UnityEngine;
using System.Collections;

public class CameraFollow : MonoBehaviour {
	public Transform target;

	// Update is called once per frame
	void FixedUpdate () {
		float cowX = target.position.x + 2;
		float cameraZ = transform.position.z;
		float cowY = target.position.y;
		Vector3 move = new Vector3(cowX, cowY, cameraZ);
		iTween.MoveUpdate(gameObject, move, 0.0f);	

Try replace FixedUpdate to Update.
I think it will work