Weird Cap Behavior

In the attached file I have a solid that I created using advice received from another post.

However, I started getting all kinds of weird behavior one the same surface that is causing problems the attached example. In the original file, joining the surfaces created a closed polysurface but it looked like this:

After I copied the source to a new file, I got a different weirdness with the same surface. If I try to cap the polysurface, it creates the cap but does not join all the edges.

I get the same problem if I create the pentagon surface using planarsrf.

I am curious what is going on here and how I might correct.

Problem74.3dm (1.4 MB)

Zoom in on your side surfaces - they’re folded over on themselves at one spot. Not good geometry at all… --Mitch

If I am seeing what you are seeing, then what is creating that? In the attached, I have the frames that I used for a networksrf.

Problem75.3dm (181.7 KB)