Ok… That is an interesting fact… If you move them away from the other objects can you loft it and then move it back?

I am not a FreeCad user, but in every other 3D package I have used the answer to this question is one of the following: self-intersecting profiles, non-closed profiles, or too great an angle on the loft path (which would create an invalid solid). Check for these issues and I’ll try to open this file in AutoCAD later this evening.