Can’t check your code as you’ve only provided screenshots and unformatted text.
If you check the geometry closely in the file you provided, you can see that the segments you indicated do in fact have a very small overlap (approx. 6E-11 units).
(Text Dots in this image indicate curve edit point locations.)
If you explode the curves in your file and process all intersection events, the result is 5 single point intersections and 2 overlap intersections.
You can see the segments at index 4 from both curves produce this small overlap.
(Text Dots indicate curve segment indices. Data paths of the intersection events indicate which curve segments produced the intersection event.)
I just noticed that you are using a cracked version of Rhino.
I thought about deleting the info. I posted above but since I took the time to investigate I will leave it.
Do the right thing and buy a license if you want to continue using Rhino.
-Kevin