The post is originated here https://developer.vuforia.com/forum/unity/unity-560f3-vuforia-6210-hololens-objecttracking
and it is closed but I still have issue after trying the suggested fixed. So I just reopen it here.
Basically, When using Vuforia 6.2.10 with Unity Editor 5.6.x on HoloLens, the Y-axis transform of an augmentation, parented by an ObjectTarget prefab, is inverted.
Any other suggestion is very much welcome.