Menus are not displayed on all pages

Hi

it’s quite strange and I’m not sure that the problem is linked with the theme; but I will ask anyhow – maybe someone has an idea.

I have 2 Menus in the online-shop (standard menu and a max mega menu); Both are displayed as I want it.
One exception: The basket page – there is no menu to be seen.
If you wantI can upload some pics to show the problem.
Ciao
vanbrel