User blog comment:Rappy 4187/Technical Update: December 4, 2012/@comment-452-20121205201643/@comment-957747-20121205213821

This is actually a limitation of core MediaWiki and still exists in MW 1.21 (wikipedia:User:Rappy4178). This would be an issue to report to them in hopes that core MW gets fixed.

When editing a section, the editor only has the header as an anchor when redirecting back to the saved page. I don't think that it is possible, without a complete rewrite of the way sections are edited/save, for this to work as we'd expect with identically named section headers.

As far as my comment you linked, I apparently mis-understood what you were describing.