Material ID with PBR surfaces not working?

SnowSultan

Just want to confirm something: I assigned material ID colors to some of the surfaces in a scene and then rendered with a Material ID canvas. However, nothing that used a PBR material was colored differently, they all just rendered solid black. Is this expected behavior or do you have to do something different to get their Material ID colors to show up? Thanks.

edit: It appears that all surfaces of any particular object also render with one color even if you assign different colors to each surface, effectively making the Material ID completely useless. Hopefully someone can confirm that I'm not missing something. Thanks.