Depth Mask problem

I’m trying to figure out how to use a depth mask with the Google VR SDK,
at the moment I’m getting this funky outcome which is not what’s meant to happen.

The shader I am using is the one below with a Set Render queue script on GameObjects I’m punching holes through, everything works fine in the editor but appears messed up when testing on the Google Pixel 2

Shader "Masked/Mask" {
    SubShader {
        // Render the mask after regular geometry, but before masked geometry and
        // transparent things.
        
        Tags {"Queue" = "Geometry-10" }
        // Don't draw in the RGBA channels; just the depth buffer

        Lighting Off

        ZTest LEqual // added this
        ZWrite On

        ColorMask 0
        // Do nothing specific in the pass:
        Pass {}
    }
}

Additional info:
Unity 2017.4.12f1
GoogleVRForUnity_1.170.0
Using 32-bit Display Buffer
Color Space: Gamma
Graphics APIs:
-OpenGLES3
-OpenGLES2
Depth Format: 16-bit depth

Hi vonbetelgeuse

Did you figure out the issue?