Hi Micha, just to give you a better idea on how coarse 16 degrees is (and to better illustrate what is happening), here I have extracted that fillet piece and viewing it from the side where it is curved, I have placed 2 line segments underneath it which have a 16 degree deviation between the lines:




As you can see, the fillet overall does not really bend as much as those line segments bend with respect to one another - that's why an angle of 16 degrees does not cause that fillet to be subdivided in that direction, it is within that angle tolerance.

Again also notice that the angle between the lines is very noticable - that is because 16 degrees is a pretty coarse angle! As you can see lines that are at 16 degrees to one another do not look very much like a smooth curve.

When you generate a coarse mesh you can get that kind of "non-planarity" to n-gons which is what causes those kinds of kinks.

- Michael