Hi,
It is drawn as a correct circle. ;
http://4.bp.blogspot.com/-HucA11UkVJ...0/RSCN1711.JPG
The camera angle is affecting how it looks.
If you were to scale it up the camera would be out past a line square to the end marker. A vary oblique view.A little worse than any parallax the judges have to account for when they observe end manouvres. It does show how this can be an issue for pilots and judges.They will never all get on the same page.

Briam