Jim, you're right.

While removing the smoothing groups did remove the P6 rendering artifacts at the triangulated facet, it did not help at the interface between body parts. These would appear to be two different problems. I focused on the triangulated facet and was wrong to assume the fix would apply to both.

I'm not sure that any program should automatically, physically weld body part seams. That changes the geometry and would screw up morph targets. I don't think P5 does this. I do think that P5 is more forgiving than P6, applying some sort of smoothing that I can't turn off. Perhaps P6 has to do things differently, more strictly, to allow the new crease angle feature, or perhaps it is a bug.

Jeff