When you create a new navigation item in a hub site navigation, there is no option to leave the URL blank. The top level menu items have to link to something. If you leave it blank, you can't save it. If you add #, it links to the root. When you have sub items, the natural behavior is to click on the menu to see the children. This is causing a page reload.
Does anyone know a workaround to not have the top level navigation item link to anywhere?