The site menu on WordPress does not work correctly, why can this be?

Question

User navigation

in the admin panel like this:

but in reality like this:

why this can happen and how to fix it so that only the necessary pages are displayed in the menu.

Answer 1

get into the template in the place where the menu is displayed and see what the template actually displays instead of the menu, and then fix it.

Answer 2

In the menu section there is a "Manage Areas" section, or at the bottom under the menu structure there is a "Settings" Theme Areas. There, specify where the menu you created should be displayed.