Hi rom, so it's not that the skinny tris are reversed exactly, it's that the n-gon that they are carved off of is non planar enough that they are ending up pivoted quite a bit.

Here's what I mean, this is a side view of one of them:





Then it seems like your render engine does not like having a little face that has a face normal deviating quite a bit from surrounding other face and vertex normals, it probably gets the surrounding area dark by thinking it's in a shadow. (if there is an option for raytraced shadows bias factor bumping it up could reduce this "self shadowing" effect)

Was this fillet made in MoI v5? It kind of looks like there is just a little too much of a gap between the fillet surface and the cylinder which looks like it contributes to making the n-gon more non-planar. If this is coming from the new ACIS fillets in MoI v5 it would probably help if I tightened up the fitting accuracy for the conversion from ACIS just a little bit more.

If you turn on the moi.ini flag CentroidTriangulation=y as mentioned above, it should prevent these types of tris from being generated. With that enabled, n-gons will get triangulated like "slices of pie" from each n-gon edge to a centroid point (when possible).

Also this problem should automatically get reduced with an increased density of polygons. That's because when n-gons are larger and span a larger area of a surface the degree of non-planarity is also increased. As n-gons get denser they occupy a smaller region of a curved surface which naturally acts more and more like a plane instead of a curve.

So there are a few different things I can try to prevent this. First is if it's a new problem showing up particularly with fillets done in v5 I can probably tune the accuracy of that up. I have a few other ideas to experiment with as well.

Thanks, - Michael