If one clicks the "Docs" link on the upper hand side of the website, the redirection is wrong.
However, the link on the left side ("Documentation/Documentation List") works fine and shows the "new" documentation web site.
Well, the 'Docs' link works fine for me (it links me to http://www.gentoo.org/doc/en/), although if you click on "Documentation/Documentation List" and then click on "English" (which links to http://www.gentoo.org/doc/en/index.xml) it shows the "3. Configuring your Network" paragraph from some (old) handbook.
Huh, http://www.gentoo.org/doc/en/ shows "3. Configuring your Network" for me.
I cannot reproduce the behavior. All noted pages render what they are expected to.