Yes, I expect that the menu always will fit within the 100% screenwidth.
So without scrolling.
It not only appears when reducing the screensize on a desktop to minimum (which is not really a problem), but it appears immediately on my iPhone 14 mini.
Especially on a mobile phone horizontal scrolling of the bottom menu is useless.
The complete website fits within the screenwith, so I expect the bottom menu to do the same. So the menu should be full responsive.