mobile page not showing correctly…?

Hi,

when I work in customizer, my mobile page looks fine, however when I see the actual mobile page:
at the bottom is a bar with ‘my account’ – ‘search’ – and ‘cart’ permanently locked on screen, when you look at the page on a mobile it’s an empty bar; the buttons are there and they work, but you can’t see them, which is very confusing…
What can be causing this?

regards
evi