unity3d - Vuforia Cloud Recognition not working properly for the first few detection in Unity -

i making app using vuforia , unity. have implemented vuforia cloud recognition in project , working 1 issue.

what doing right is:

1. added markers vuforia cloud service.
2. in metadata of marker have added url of asset bundle download game objects render on marker after detection.
3. after game object downloaded, fetch names of prefabs downloaded asset bundle , show them in list user select game object want display.
4. when user select item list instantiate prefab , make child of imagetarget.

this how this.

   public void onlistitemclick(gameobject namegameobject)     {         string name = namegameobject.transform.parent.name.tolower();          objecttoaugment = (gameobject) bundle.loadasset(name);          if (parentobject.transform.childcount>=1 || parentobject.transform.childcount==0)         {             if (parentobject.transform.childcount >= 1)             {                 destroy(parentobject.transform.getchild(0).gameobject);             }              objecttoaugment = instantiate(objecttoaugment, parentobject.transform);             objecttoaugment.transform.localrotation = new quaternion(0, 90, 0, 1);             objecttoaugment.transform.localposition = new vector3(0, 0.1f, 0);             objecttoaugment.transform.localscale = new vector3(0.1f, 0.1f, 0.1f);             objecttoaugment.addcomponent<leanscale>().requiredfingercount = 2;             objecttoaugment.addcomponent<leantranslate>().requiredfingercount = 1;          } } 

this make child of image target instantiated object doesn't follow vuforia image target behaviors.

for eg. instantiated object doesn't move when image target moved, stays @ same place instantiated.and during time vuforia events tracking lost , tracking found not called @ all.

however, if remove/show image target few times camera fov, starts recognizing image target , model shows @ correct position , scripts methods called after that.

i unable pinpoint exact issue here.

edit:

this seems bug vuforia cloud services. days works while other days start giving these problems. experienced ?