Imteresting!  My first time browsing the forums here and I  stumble aross this post. I too have experienced P7 texturing render mixup. In my case I was doing a render that had an imported background image. Instead of the background image I imported, The figure's texture map was being rendered as a background. 
I was thinking it was one of Poser's notorious resource hogging issues since it happened after I had been working on a fairly complex scene with quite a few figures and props in it. Shutting down Poser and reopening it, the scene rendered correctly.

Hey! His nose is dry! ... Someone should lick it,  just in case. - Diego