Then again, Poser sometimes just goes all wonkey for no reason.
This is a screencap where I tried to tweak a pose and two fo the figures (parented together) kind of exploded. It wasn't a visual artifact, either, I tried exporting as an OBJ, and it was the same mess.
Wan't the fault of the figures, or the poses, that I could see specifically - just Poser oddness.