Hi,

    I put a 3D model on the ground,it is steady. It will float after I shelter the camera like  looking at the wall  or shaking my iPhone hardly.And some error output in Xcode as follows:

NullReferenceException: A null value was found where an object instance was required.

  at PlaneManager.HandleInteractiveHitTest (Vuforia.HitTestResult result) [0x00000] in <filename unknown>:0

  at UnityEngine.Events.UnityEvent`1[T0].Invoke (.T0 arg0) [0x00000] in <filename unknown>:0

  at Vuforia.PlaneFinderBehaviour.PerformHitTest (Vector2 screenPosition) [0x00000] in <filename unknown>:0

  at UnityEngine.Events.UnityEvent`1[T0].Invoke (.T0 arg0) [0x00000] in <filename unknown>:0

  at Vuforia.AnchorInputListenerBehaviour.Update () [0x00000] in <filename unknown>:0



(Filename: currently not available on il2cpp Line: -1)

HandleInteractiveHitTest() called.

PlaneManager:HandleInteractiveHitTest(HitTestResult)

UnityEngine.Events.UnityEvent`1:Invoke(T0)

Vuforia.PlaneFinderBehaviour:PerformHitTest(Vector2)

UnityEngine.Events.UnityEvent`1:Invoke(T0)

Vuforia.AnchorInputListenerBehaviour:Update()



(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

The refresh button will help but it could not be as steady as the beginning and this experience is not good for client.How can I fix this issue.