Curved isocurve and edge disparity on extruded-like surface ¿why?

Good day,

As visible in the file the top and bottom control points are in the same X and Y, but edges have a different curve. Vertical and horizontal isocurve are off to that logic.
Untrimming all eges didn’t make anything perceivable.
Extruding a new surface from a duplicated edge produces a standard “correct” extruded result.
Why does this happen?

Have a nice day!

curved isocurve and edge disparity.3dm (56.6 KB)

Hi @X111
Control points have different weights - so someone or something changed the weights.
HTH, Jakob

Hello Jakob,

Thank you very much for your explanation.

It’s the first time Ihear about that. I’ll try to find out more to better understand it.

I wish you a good week,