Haven't rebooted my computer, but I have restarted Poser several times.  I'll try a reboot and report back.  I don't think its the UV map either.  I decided I didn't like parts of the mesh and went back and rebuilt parts of it to reduce the poly count, remapped the UV, exported as OBJ, imported to Poser and... same issue appeared.

Its only with the one red marble MAT that as I recall came with Poser 6.  It also seems to have something to do with the lights.  If I turn shadows off on two of the 3 default lights, I noticed the effect seemed to change. 

But at least Poser is consistent!  LOL   Just trying to sort it out, I'm intending to release these for sale so I want to make sure there are no issues.

Off to reboot.