Since this is more a discussion topic I don't enter it in the bugtracker:
(quote from the tracker)
It is as a PDN blocker as it is a Part blocker, i.e. the same issue happens in PDN.
A blocker is (to me) an issue prohibiting roll out of a stable version. Since the behaviour exists for years, probably since Loft exists, I don't think it should block v 0.17.
I am not sure that profile is overtwisted (as per documentation). I would tend to think that if the one half of the arc was possible, the other half should be possible as well.
What I understand from the documentation is that if the twist would me more than 45º, the selection of correspondance would change so as to minimize the twist.
The documentation is clear about angles < 45° degrees. They are not twisted. That may imply that for angles >45° the loft has to be twisted, because the opposite angle is less than 45° degrees. Alas, the docs say nothing about an angle = 45°, and that's what we have here twice. So it boils down to a precision issue, one of the angles being less and one being greater than 45° degrees. The only thing we could do to make it unique is to prohibit lofting if an angle=45° is recognized.