An overlay analysis between some polygons and a few lines has turned into quite the ordeal.

I hope the supplied workspace and data is self-explanatory.

In it there is four tests that yield different results.

I start with clipping the lines with the polygons followed by a spatial relator intended on creating a list of references. I would expect that relator would find a relation between all lines since they can only be INSIDE. But more than half fails.

To test the reason I run it through an Intersector and measure the distance from intersection node to polygon mask. I guess that is supposed to be 0, but 3 of 20 return a value larger than 0 - meaning that the intersectionnode is not in the intersection.