Viewport rendering incorrect switching from AR to VR Vuforia 6.2.10 Unity 5.4.2f2

Hi,

I need help about this issue:

If I try the AR/VR sample all run correctly on iOS 10 BUT in that sample the switch is in the About scene, then unless AR initialized.
My app run in AR and when I focus a marker I shows a button to switch to the VR, this is the screenshot about the viewport rendering:




The viewport is not in stereo mode, the gaze isn't centered and there isn't any settings for the cardboard.
In the Digital Eyewear settings I use Video See-Through, Vuforia as Stereo Camera Config and Cardboard v1 (Google) as Viewer type but if I change to another viewer the result is the same.

What I don't understand is why the sample app run correct and my app not, they are the same settings.
Someone had experience with mix AR/VR or this issue?

Many thanks!