Anchoring in Vuforia

I'm able to fix the position of the object once it's spawned. But, the object is placed onto different position on every tap on the screen. I want to avoid this problem and want my object to be fixed in a spawned position throughout the Session or Application lifetime.

This is my Deploy Stage Once script:

public class DeployStageOnce : MonoBehaviour
{

    public GameObject AnchorStage;
    private PositionalDeviceTracker _deviceTracker;
    private GameObject _anchorGameObject;
    private GameObject _previousAnchor;

    public void Start()
    {
        if (AnchorStage == null)
        {
            Debug.Log("AnchorStage must be specified");
            return;
        }
        AnchorStage.SetActive(false);
    }
    public void Awake()
    {
        VuforiaARController.Instance.RegisterVuforiaStartedCallback(OnVuforiaStarted);
    }
    public void OnDestroy()
    {
        VuforiaARController.Instance.UnregisterVuforiaStartedCallback(OnVuforiaStarted);
    }
    private void OnVuforiaStarted()
    {
        _deviceTracker = TrackerManager.Instance.GetTracker<PositionalDeviceTracker>();
    }

    private void AnchorGameObjectSetHitTestPosition(HitTestResult reuslt)

    {

        _anchorGameObject.transform.position = reuslt.Position;

        _anchorGameObject.transform.rotation = reuslt.Rotation;

    }


    public void OnInteractiveHitTest(HitTestResult result)
    {
        if (result == null || AnchorStage == null)
        {
            Debug.LogWarning("Hit test is invalid or AnchorStage not set");
            return;
        }
        var anchor = _deviceTracker.CreatePlaneAnchor(Guid.NewGuid().ToString(), result);
        _anchorGameObject = new GameObject();
        AnchorGameObjectSetHitTestPosition(result);
        if (anchor != null)
        {

            AnchorStage.transform.parent = _anchorGameObject.transform;

            AnchorStage.transform.localPosition = Vector3.zero;

            AnchorStage.transform.localRotation = Quaternion.identity;

            AnchorStage.SetActive(true);

                    }
        if (_previousAnchor != null)
        {
            Destroy(_previousAnchor);
        }
        _previousAnchor = _anchorGameObject;
    }
}