Material functions using Vertex Interpolators called by multiple function nodes will only use the final interpolator result

The interpolator in each function call does correctly compile it's input to a temporary, but as there's only one actual expression node, each call stomps the temporary data so the final CompileInput call "wins". All compile calls on the interpolator's output end up using the last value only. The node should store the associated function-stack when the input is compiled so each instance can be routed correctly.

• Create a Material Function and connect an input to Vertex Interpolator then that to the output.
• Create a material and add two function call nodes looking at the previous function.
• Hook a separate vector parameter to each.
• Hook the outputs to base color and emissive color.
• Note the final material only respects one of the values (Also viewable in the generated HLSL).