Overlay material doesn't cover entire mesh?

I dragged in a quinn mesh (qinn simple to be exact) and put a basic wall material as the overlay, but it only seems to cover material index 1.

It’s clearly something in the quinn_01 material instance that’s causing it, but what could it be?

If I set both slots to quinn_02 instead it will cover the whole mesh


Which is quite odd considering quinn_02 is a child of quinn_01.