Exploding Exported Polyline

Hello
I’ve received some lines from a stp file, when I explode them they change positions.
And when I activate PointsOn, this occurs [see image bellow]. The dotted line Is exactly the shape it takes when I explode it.
Is there a simple way to explode correctly ?

image

Best Regards
A

Can you post a small example (STEP file and resulting Rhino import)?

–Mitch