Flicker while detecting edge of screen with Mathf.clamp

Hi guys, im stucking for long hours to find this solution.. the object is always flickering when moved to the edge x (left and right).. moving to top and bottom are working well.. this is the code..

But there are some details you needed to know..

Clamp Min and max are configured in Start()

UpdateMovement is called on Update()

Thank you for your help

 void Start(){
         m_clampMinX = Camera.main.ScreenToWorldPoint (new Vector2 (0 + clampMarginMinX, 0)).x;
         m_clampMaxX = Camera.main.ScreenToWorldPoint (new Vector2 (Screen.width - clampMarginMaxX, 0)).x;
         m_clampMinY = Camera.main.ScreenToWorldPoint (new Vector2 (0, 0 + clampMarginMinY)).y;
         m_clampMaxY = Camera.main.ScreenToWorldPoint (new Vector2 (0, Screen.height + clampMarginMaxY)).y;
     }
 
     // The clamp margins
     public float
     clampMarginMinX = 0.0f,
     clampMarginMaxX = 0.0f,
     clampMarginMinY = 0.0f,
     clampMarginMaxY = 0.0f;
 
     // The minimum and maximum values which the object can go
     private float
     m_clampMinX,
     m_clampMaxX,
     m_clampMinY,
     m_clampMaxY;
 
 
     void UpdateMovement()
     {
         foreach (Touch touch in Input.touches)
         {
             switch (touch.phase)
             {
             //When just touch
             case TouchPhase.Began:
                 //detect touch hit the collider in player or not
                 touchBegin = Camera.main.ScreenToWorldPoint (Input.mousePosition);
                 Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
                 RaycastHit2D hit = Physics2D.Raycast(ray.origin, ray.direction);
 
                 if(hit != null && hit.collider != null){
                     if (hit.collider.gameObject.tag.Equals("Player")) {
                         gameObjectTodrag = hit.collider.gameObject;
                         GOcenter = gameObjectTodrag.transform.position;
                         touchPosition = Camera.main.ScreenToWorldPoint (Input.mousePosition);
                         offset = touchPosition - GOcenter;
                         draggingMode = true;
                     }
                 }
                 break;
 
             case TouchPhase.Canceled:
                 animator.SetInteger (DIRECTION, 0);
                 break;
             case TouchPhase.Stationary:
                 animator.SetInteger (DIRECTION, 0);
                 break;
             case TouchPhase.Moved:
                 if (draggingMode)
                 {
                     touchPosition = Camera.main.ScreenToWorldPoint(Input.mousePosition);
                     if (touchBegin.x > touchPosition.x) {
                         animator.SetInteger (DIRECTION, 2);
                     } else if (touchBegin.x < touchPosition.x) {
                         animator.SetInteger (DIRECTION, 1);
                     }
                     touchBegin = touchPosition;
 
                     newGOCenter = touchPosition - offset;
 
                     gameObjectTodrag.transform.position = new Vector3 (
                         Mathf.Clamp (newGOCenter.x, m_clampMinX, m_clampMaxX),
                         Mathf.Clamp (newGOCenter.y, m_clampMinY, m_clampMaxY),
                         GOcenter.z);
                 }
                 break;
 
             case TouchPhase.Ended:
                 animator.SetInteger (DIRECTION, 0);
                 draggingMode = false;
                 break;
             }
         }
     }

s