Ebookie is a one page theme. This means each page becomes a part of one big page. Each page is also automatically a link to that part of page so when user clicks on the link he is taken to the part of the page that corresponds to it. This means that no menu is necessary as all menu items are created automatically when a page is created.
So why this happens?
Because of ThemeForest requirements, a separate (standard) wordpress menu has to be present in order to consider theme valid. When this function is implemented into a theme a menu is created automatically by WordPress when no menu is present/set. This would be fine on a regular theme, but in ebookie we already have a menu created from pages.
How to fix it?
You have to create an EMPTY menu and assign it in WP backend. Go to Appearance > Menus, click Create a new menu and leave it empty. Then click the tab Manage Locations and assign this empty menu to theeBookie Menu location. That’s it. This will prevent wordpress to assume that you have no menu and prevent creating 2 menus.