Simple shader showing in 2019 editor but not on device

Trying to get my feet wet with shaders, so I created a small prefab that reflects a target in the ground that is using a shader to mimic occlusion.

This seems to work quite nicely in 2019's editor, but when I run it as a build on different platforms (osx, win, android). they all don't seem to cull the geometry as it does in the editor.

Here's the shader code:

Shader "Custom/HoleShader" {

    SubShader

    {

        Lod 100



        Tags

        {

            "Queue" = "Geometry-1"

            "RenderType"="Opaque"

        }

       

        Pass

        {

            ZWrite On

            ZTest LEqual

            ColorMask 0

            Cull Back

        }

    }

}

Editor:



Device: