Jan. 2018, using Acrobat v11.0.23. In the index, on p. 35, left column, lines 4 and 6, the links to section 503 do not take me there when I click them. I checked them by going to Tools | Interactive Objects | Select Object, right-clicking each one in turn, and choosing Properties | Actions. The Action shows as "Go to a page in another document," which is correct. However, the File shows as "C:\(the path to the PDFs)\.pdf" rather than "C:\...\mpep-0500.pdf". It does have a destination name, e.g., "d0e28636" for the link on line 6.
This is the case elsewhere as well. E.g., p. 60, left column, line 10 ("Identification"): the link to section 502 has the filename and works, and the link to section 503 does not have the filename and does nothing when clicked.
Thanks for looking into this!