Shader not working with HDR

I have a shader that I use for minimap FOW.
The base shader was taken from here and modified to work with Unity 5

Code (CSharp):

1. Shader "Custom/FogOfWarMask" {
2.     Properties{
3.         _Color("Main Color", Color) = (1, 1, 1, 1)
4.         _MainTex("Base (RGB)", 2D) = "white" {}
5.     }
6.     SubShader{
7.             Tags{ "Queue" = "Transparent" "RenderType" = "Transparent" "LightMode" = "ForwardBase" }
8.             Blend SrcAlpha OneMinusSrcAlpha
9.             Lighting Off
10.             LOD 200
11.  
12.             CGPROGRAM
13. #pragma surface surf Lambert alpha:fade
14.  
15.             fixed4 LightingNoLighting(SurfaceOutput s, fixed3 lightDir, float aten)
16.             {
17.                 fixed4 color;
18.                 color.rgb = s.Albedo;
19.                 color.a = s.Alpha;
20.                 return color;
21.             }
22.  
23.             fixed4 _Color;
24.             sampler2D _MainTex;
25.  
26.             struct Input {
27.                 float2 uv_MainTex;
28.             };
29.  
30.             void surf(Input IN, inout SurfaceOutput o)
31.             {
32.                 half4 baseColor = tex2D(_MainTex, IN.uv_MainTex);
33.                 o.Albedo = _Color.rgb * baseColor.b;
34.                 o.Alpha = clamp(_Color.a - baseColor.g, 0, 1); //green - color of aperture mask
35.             }
36.             ENDCG
37.         }
38.         Fallback "Diffuse"
39. }
40.  

It works fine without HDR or other post processing effects running.
Soon as HDR is enabed the shader stops working.
Or at least it looks like it is not working in the game view.

Is there a certain command I need to add so it will work with HDR?