Mmm I'm looking a little more closely to the MoI tesselation, and I'm not really sure now if MoI is not doing something weird too on this particular model.
I have a 'deja-vu' feeling here, but I dont remember if it's 'normal' or not.

Here's a closup of the knob in MoI,



It's really strange that ngones and quad output dont give the same shading result in MoI either.