@Mike-Amos thanks Mike!

What do you mean by changing the order? Do you mean selecting them in a different order before execution?

I have been using the skin function with the whole shape selected before pressing the button.

Thanks for the replies.
I made sure that the arcs have the same number of segments (40).

Curviloft problem.skp

I tried Extrusion Tools, it had the opposite problem. The seam bulged outward instead of curling inward.

Hello!
Curviloft is awesome! I am trying to use it for this task:
I want to loft this -

Into this -

So far, so good. But the precise shape is important. The result has this deformations (copied into 4 corners):

In all 4 corners where the quarter portion is connected, there is a curl inward. The transition is from a perfect circle to a rounded rectangle with all angles bulging outward, there is no inward crease in the base shape:

It still happens, whether I do it in quarters, or halves, or the whole shape at once. See the creases going inward where the quadrants meet. I have tried every combination of settings in the curviloft options. What am I doing wrong? Anyone know how to get a basic loft that follows the geometry, without adding the inflection inward?

Thanks!