Why some non-solid shapes do not allow 'Edit Points' in Powerpoint

Question

Imagine that I import an .emf (made from .svg) file to MS Powerpoint (2013 or 2016) like so.

This is an icon, so I'm about to edit it with Edit Point context menu capabilities. I import the picture to a presentation file and Ungroup it (I've added greet color to the background for visual contrast). So far so good.

Now I can take separate parts of the shape (not a picture any longer). As you can see, I can edit the head of the child.

But obviously not the body, which is a kind of "non-solid" shape (!).

Why is it so? What kind of shape is that? (Not sure how to call this kind of shape anyway.) Is there a workaround?