Did you found a solution? I run into the same problem. We want to have the top-level of the main menu non-clickable (we don’t have any page for it), so I use custom-links and set the URL to #. But then your burger menu don’t know how to handle clicks on the top-level menu entries as long as the “Menu Item Submenu Items” entry is set to “Display submenu items on click” (on hover works, but we don’t like the handling).

That you have the option not to clone the title menu or not looks like you have support for the idea to have an non-clickable top level, but I have no idea how I must create the menu so that this works.