Why is my Fade Post Processing effect no longer working?

I had a fade effect on my camera to fade in/out. When I was in Unity 5.5 it worked fine, but now that I upgraded to 5.6 it no longer works. Was something changed with how post processing works now?
Any ideas and suggestions would be appreciated.
Here is the code I am using:
public class Fade : MonoBehaviour
{

    [SerializeField]
    private Color _colour = Color.white;

    [SerializeField]
    [Range(0, 10)]
    private float _fadeSpeed;

    [SerializeField]
    [Range(0, 1)]
    private float _alpha;

    [SerializeField]
    private Material _material;

    private void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        _material.SetColor("_Color", _colour);
        _material.SetFloat("_Alpha", _alpha);
        Graphics.Blit(source, destination, _material);
    }

}


Shader "Post Processing/Fade" 
{
    Properties{
        _Color("Color", Color) = (1,1,1,1)
        _MainTex("Texture", 2D) = "white" { }
    _Alpha("Alpha", Range(0,1)) = 1
    }
        SubShader{
        LOD 200
        Tags
    {
        //"Queue" = "Transparent"
        //"RenderType" = "Transparent"
    }

    Pass{
        Blend SrcAlpha OneMinusSrcAlpha


        CGPROGRAM
#pragma vertex vert
#pragma fragment frag

#include "UnityCG.cginc"

        float4 _Color;
    sampler2D _MainTex;
    float _Alpha;

    struct v2f {
        float4  pos : SV_POSITION;
        float2  uv : TEXCOORD0;
    };

    float4 _MainTex_ST;

    v2f vert(appdata_base v)
    {
        v2f o;
        o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
        o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
        return o;
    }

    half4 frag(v2f i) : COLOR
    {
        half4 texcol = tex2D(_MainTex, i.uv);

        texcol = half4(_Color.rgb, _Alpha);
        //texcol.rgb = dot(texcol.rgb, float3(0.3, 0.59, 0.11));

        return texcol;
    }
        ENDCG

    }
    }
        Fallback "Diffuse"
}

Unity 5.6 is in beta. So please report any issues with it to the beta testing forum: https://forum.unity3d.com/forums/5-6-beta.125/