Reply To: Mobile menu Sub-Categories not working.

Just leave empty the field for categories menu on mobile devices in Theme Settings -> Header -> Menus. And use main mobile menu only. The title ‘Menu’ you are able to change to ‘Categories’ with the Loco translate plugin. The main point here is to have different menus created for different devices in Appearance -> Menus. One is set to be shown in mobile navigation and another one is for the desktop.