Non-Metallic parts of Mesh Unaffected by Lighting?

Hello. I’ve got a mesh with PBR material maps for it. My model appears fully lit when under no lighting. Lighting can still make it a bit brighter, but obviously this is not the desired effect, it’s way too bright to begin with. Any areas of my material I turn metallic no longer have this issue.

No metallic at all, no lights:

https://puu.sh/CeJ8X.png

Some metallic areas, which act as expected now, still no lights:

https://puu.sh/CeJbM.png