Sorry for the inconvenience. Known Navigation header breakage.
There may be other unforeseen breakage primarily in the handbook portion of the wiki.
The Table Of Contents section of each "PC-BSD® Users Handbook" page may be the best workaround.
- A new template makes the translcusion of the pages simpler by adding the lost header.
- Adding the missing header from each page allows sections to be referenced by the index that precedes them to a location on this page.
- The transclusion of the unnecessary Navheaders is accomplished by wrapping them in a <noinclude>tag set</noinclude>
As yet, it appears no further tweaks are needed.. but perhaps another template might ease the process :)