Came across something you should be aware of.
I am working on a terrain system and the first time I ran it, the terrain was white.
After a bit of digging about I found the problem in the pixel shader.
It's not finished, but should have worked.
My vertex shader outputs a structure
float4 position : POSITION;
float4 uv : TEXCOORD0;
float4 worldPos : TEXCOORD1;
float4 textureWeights : TEXCOORD2;
My pixel shader initially was .....
float4 PixelShader(in float4 uv : TEXCOORD0, in float4 weights : TEXCOORD2) : COLOR
And I had white terrain indicating the weights was wrong.
I changed it to ....
float4 Pixel(VS_OUTPUT input) : COLOR
And all of a sudden my terrain was textured.
Do you use a bespoke shader compiler?