Hi Radiance

I made a single flat poly in MoI. The vertex normals are totally different.

mtllib SingleflatPolygon.mtl
o object1
g object1
v 0.00000000 3.13267827 -0.00000008
v 0.00000000 -11.46117210 -0.00000008
v 33.88950729 -11.46117210 -0.00000008
v 33.88950729 3.13267827 -0.00000008
vt 1.00000000 1.00000000
vt 0.00000000 1.00000000
vt 0.00000000 0.00000000
vt 1.00000000 0.00000000
vn 0.00000000 0.00000000 1.00000000
vn 0.00000000 0.00000000 1.00000000
vn 0.00000000 0.00000000 1.00000000
vn 0.00000000 0.00000000 1.00000000
s 1
usemtl Default
f 1/1/1 2/2/2 3/3/3 4/4/4