Hi Mike, wow that is an awesome looking result!

Do you happen to have a file saved with the curves in it that made that sasaugey type sweep result? There is a process that tries to align profiles to reduce twist and also to flip them if needed so that doesn't happen but it looks like it's not working there. But also it may just be getting confused because you've got a quite significant change in shape in just one single step there, if you had one more sort of in-between step there instead of a sudden shift from convex to concave all in one go it could probably help it to get it right.

- Michael