Why there are three points created when intersect between 1 nurbscurve and 1 Surface in Dynamo Coding

Hi All,
with my below coding for intersection between 1 nurbscurve and 1 surface. this should be 1 points as per Dynamo script, but from my code which created 3 points…
not sure anyone having same situation?


Not sure where two additional Points come from? Try to show manually in dynamo script as below? but the distance from these two points to the Surface is 0? really STRAIGHT.