Loft weird

Hello, i would like to know why when making this loft it makes two surfaces. Thanks!!!

Please be more specific.

this is the file (5.2 KB)

Looks like one of your curve has a kink of it’s control points. (7.7 KB)

additional to Kims proposal:
You can loft it through C#,it seems a refit is done automatically.

Also you could do it in the loft options

hello, I did the rebuild in the loft options and it works!!! Thanks a lot