Secondly, I also expect that conic arcs (parametric surfaces form conic arcs?) have an impact in creating that fold/crease. I know I could report this as a bug, but I think that the loft algorithm is built as it is purposely, and it fails in this example, not because of a bug, but rather because of some principle rules. Eventually, I do also use MoI blend tool to show how this transition should look like: Below you will see another gif, I've added one more example where I use conic arcs but instead of an Extrude, I use Loft, to get NURBS from conic arcs. I was guessing that it could be because of conic arcs (it looks for me that extrusion of a conic arc doesn't build NURBS surface, but rather some kind of parametric surface), so with the second approach (darker blue) I've used spline, and while it looks a lot better it has the very same problem. The first model (light blue) is the original approach, and you can see an awful fold/crease on a lofted surface. The shape is trivial and didn't expect to have any problems, but unfortunately, I do have. I do design a handle (for a toolbox or similar type of case), to define its shape I use mainly conic arcs.

Hi everyone, I do have a problem with a loft command.

Loft in fusion 360