Clip Shader not working on a few Android devices

I have a shader that is supposed to Clip images. For the materials that need to be clipped, the Clip is set to 1 and for others it is set to 0. When Clip is 0, it works fine on the Galaxy Note4. However it simply doesn't render on the Nexus 5 and OnePlusX. Shader "ClipRect" {

   Properties {
     _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
     _Alpha ("Alpha", Range(0,1)) = 1.0
     _Clip ("Clip", Int) = 0
     _ClipRect ("ClipRect", Vector) = (-5000, 5000, 5000, -5000) // left, top, right, bottom
   }
 
   SubShader {
     Tags {
       "Queue"="Transparent"
       "IgnoreProjector"="True"
       "DisableBatching"="True"
       "ForceNoShadowCasting"="True"
       "RenderType"="Transparent"
     }
     LOD 80
     
     Cull Back
     Lighting Off
     ZWrite On
     ZTest Always
 
     Blend SrcAlpha OneMinusSrcAlpha
 
     Pass {  
       CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #pragma enable_d3d11_debug_symbols
 
         #include "UnityCG.cginc"
 
         struct appdata_t {
           float4 vertex    : POSITION;
           float4 color     : COLOR;
           float4 texcoord  : TEXCOORD0;
         };
 
         struct v2f {
           float4 vertex     : SV_POSITION;
           fixed4 color      : COLOR;
           half2 texcoord    : TEXCOORD0;
           float4 clipcoord : TEXCOORD1;
         };
 
         sampler2D _MainTex;
 
         float4 _MainTex_ST;
         float  _Alpha;
         int    _Clip;                          
         float4 _ClipRect;     // left, top, right, bottom
 
         float4x4 _SpriteToClip;
 
 
         v2f vert (appdata_t v) {
           v2f o;
           o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
           o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
           o.color = v.color;
 
           o.clipcoord = mul(_SpriteToClip, v.vertex);
 
           return o;
         }
         
 
         float4 frag (v2f i) : SV_Target {
           fixed4 col = tex2D(_MainTex, i.texcoord);
           bool bKeep = true;
 
           if(_Clip != 0) {
             if(i.clipcoord.x < _ClipRect.x ||
                i.clipcoord.x > _ClipRect.z ||
                i.clipcoord.y > _ClipRect.y ||
                i.clipcoord.y < _ClipRect.w) {
               bKeep = false;
             }
           }
 
           if(bKeep) {
             col.rgb *= col.a;
             col.a *= _Alpha;      
           } else {
             discard;
           }
 
           return col;
         }
       ENDCG
     }
   }
 }
 

It seems like the logic is right but I don't know why this would not render on some devices. Very new to shaders. Any help would be appreciated.