Vertex map issue

[Burgess AK]

Hi,

Using 2019 1.3 and I am having some issues with vertex node for a material mixer. I drop a vertex node (is now black but used to be blue?) then drop my vertex map into the vertex node but it's not seeing my map. If I invert the vertex node - i get the opposite mterial just not the map itself in the render viewer. ie one material or the other but not my vertex tag map. Any ideas, probably a carbon error. Thanks