pavit
As I have already written, I have a website (http://geschichte.sophie-scholl-schule.eu ) where everything works properly. It is a problem exactly only on the website sophie-scholl-schule.eu. There must be a misconfiguration somewhere in this website.
The menu is called "Test", the corresponding article has the title "Textbeitrag".
I think I have no cdn.
If you examine the well working page with a tool, you will find the following:
<header class="article-header clearfix">
<h1 class="article-title" itemprop="headline">
<a href="/index.php/test" itemprop="url" title="Testbeitrag">
Testbeitrag</a>
</h1>
</header>
On the erroneous site one finds only this without reference to article-header:
:
<div class="page-header clearfix">
<h1 class="page-title"> Scholl-Streich-Orchester </h1>
</div>