Joystick movement getting stuck. Any Reason why?

So, I recently built a game to my phone, and I am having all my friends beta test it. The biggest problem they are all saying, is that the player gets stuck at the randomest times, and then start to move again. Or, it will start moving on its own. Here is the code:

 #pragma strict
 
 var speed : float = 5.0;
 var rotateSpeed : float = 3.0;
 var moveJoystick : Joystick;
 var rotateJoystick : Joystick;
  
 function Update () {
     var controller : CharacterController = GetComponent(CharacterController);
  
     // Rotate around y - axis
     var sideways = transform.TransformDirection(Vector3.right);
     var rotatePos = moveJoystick.position.x; 
      var Lateral= speed * rotatePos;
     controller.SimpleMove( sideways * Lateral);
     //transform.Rotate(0, rotatePos * rotateSpeed, 0);
  
     // Move forward / backward
     var forward = transform.TransformDirection(Vector3.forward);
     var movePos = moveJoystick.position.y; 
     var curSpeed = speed * movePos;
     controller.SimpleMove(forward * curSpeed);
     this.transform.position.x = Mathf.Clamp(this.transform.position.x, -12F, 12F);
     this.transform.position.z = Mathf.Clamp(this.transform.position.z, -8.5F, 8.5F);
 }
 function joyStickInput (joystick : Joystick) {
     var absJoyPos = Vector2 (Mathf.Abs(joystick.position.x),
                                    Mathf.Abs(joystick.position.y));
     var xDirection = (joystick.position.x > 0) ? 1 : -1;
     var yDirection = (joystick.position.y > 0) ? 1 : -1;
     return ( ( absJoyPos.x > absJoyPos.y) ? absJoyPos.x * xDirection : absJoyPos.y * yDirection);
 }
  
 @script RequireComponent(CharacterController)

Is there a problem in the code? Or is it something else?