Uuurrrghhh - figured it out. Related to this issue http://community.monogame.net/t/order-of-tex2d-in-shader/8720/26
So simply moving float4 tex = tex2D(InputSampler, input.TexureCoordinateA); to be the first line in the shader fixed it.
Uuurrrghhh - figured it out. Related to this issue http://community.monogame.net/t/order-of-tex2d-in-shader/8720/26
So simply moving float4 tex = tex2D(InputSampler, input.TexureCoordinateA); to be the first line in the shader fixed it.