Looking at your mat room screen caps I'd say try unplugging the B/W maps from the alpha in the principled Bsdf. I mistakenly referred to them as "alpha" when in fact that's just holdover thinking from Firefly. There's no alpha channel in those pngs, its strictly rgb channels. I keep forgetting 12 added that functionality with the Principled Bsdf. It might help to solve the weirdness you're having with the textures.