Solid Hatch: PDF Export

This one has been nagging me for a while. Here I have a solid hatch shape.

When I print the file to PDF, the hatched area is not solid but instead gives lots of little lines:

When I import the PDF back into Rhino I get all the little lines:

Is there any good way of making the hatch come out solid in a PDF?

Source file:

Problem Hatch.3dm (5.1 MB)

Based on your instructions, I can’t duplicate the problem with your file or with one of my own.
I assume this is Rhino V6 SR21.
Can you be more detailed in how you are creating the PDF file and then when Importing it?

I am finding this is a file-sensitive problem. I am trying to create a small one that reproduces it. I suspect it involves V5 file imported into V6.