Hi Rui,
we deactivated the plugins but both issues remained.
1. At the main page we integrated a google-map iframe, which seems to be the cause of the flipping when you click the logo. We removed the iframe snipped and it worked fine. What can we do to solve the problem but to keep the customized google-map?
2. Like I said, the issue with the navigation on mobile devices is still there, even with deactivated plugins.
Thank you for your help.