Why my gvr mono mode always back to stereo mode when compile to APK ?

Hei guys, I’m new user in GVR. What i wanna ask is, Why my apk always go to stereo mode VR when i already make it to mono mode ?
So when i try it in unity editor, it’s work fine, but when i compile it to android apk and try it in my smartphone, it’s always back to stereo mode. What should i do?
Even i already try to make the “VR mode enabled = false” in fixed update, but it’s doesn’t work. This is my script and my setting on build player.

public GameObject VRnya;

    // Use this for initialization
    void Start()
    {
        VRnya.GetComponent<GvrViewer>().VRModeEnabled = false;
    }

    // Update is called once per frame
    void FixedUpdate()
    {
        //Disable the VR MODE 
        VRnya.GetComponent<GvrViewer>().VRModeEnabled = false;
    }

This is the other image. This is my player setting.