Hello,
Thanks for your Valuable and Continued Patience!
We have thoroughly checked out all the codes on your Page and the possible cause of this issue according to what we have detected, is the following code:
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-about" data-scrollto="#section-about" data-offset="0">About Us</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-corporate_philosophy" data-scrollto="#section-corporate_philosophy" data-offset="0">Corporate Philosophy</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-team" data-scrollto="#section-team" data-offset="0">Team</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-partners" data-scrollto="#section-partners" data-offset="0">Our Partners</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-supervision" data-scrollto="#section-supervision" data-offset="0">Supervision</a></li>
Since this is the index.html Page and there are no Hash Sections on this Page with relative to the data-scrollto Attribute as defined on your menu items, you should be using the following codes:
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-about">About Us</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-corporate_philosophy">Corporate Philosophy</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-team">Team</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-partners">Our Partners</a></li>
<li><a href="https://www.sonnenberg-ag.ch/company.html#section-supervision">Supervision</a></li>
It is recommended to use the data-scrollto Attribute only on Pages with available Hash Sections to avoid any conflict.
This should definitely fix your issues. Hope this Helps!
Let us know if we can help you with anything else or if you find any further issues.