Not clickable Tabs on mobile (AppLayout)

Hello,

i got the Problem that on my mobile Device the Tabs for the Navigation are not clickable.
That means, the navbar is shown at the bottom and i can open the menu, but when i try to click one of the tabs, the menu is just closing and nothing else happens.
If i try this on my Computer or on my mobile with “Desktop-Site” it works.

Any ideas why it is behaving like this?

Thanks in advance!