In order to avoid duplicate links in the (side) navigation it was suggested to remove the title of the page i.e. remove the header 1 or replace it with <h1> (#308 (comment)).

However, if you do this and omit the title MkDocs fails at rendering the (side) navigation correctly as it includes more than just header 1 & 2. If you start playing around with lower rank headers the behavior becomes totally incomprehensible.

In order to avoid any such confusion and undefined(?) behavior it might make sense to introduce a new configuration parameter that defines which max header level should be included in the navigation. That was what I initially thought was going on when I posted to your group https://groups.google.com/d/msg/mkdocs/JRufth2iBaE/L_W0ZsWlDAAJ.