Vray Override Mtl Doesn't Affect TyFlow

[mitchfx]

It appears that the Vray Material Override (in render global switches) doesn't affect TyFlow geometry for some reason. I've tried both rendering as triangle mesh and Vray instances.  Same thing happens if I render a tyCache object instead.  I've also tested both include and exclude lists for the override mtl with no success. Using Max 2019, Vray Next 1.2, TyFlow 16018.