Hi there,
Thanks for writing in.
Do you have a separate menu for desktop and mobile? Or are you expecting for an inline menu to become mobile menu?
You’ll have to add different menus for each device and use its visibility option to hide each menu from other devices. It should be doable within customize section when you inspect your header elements.
Example, with inline menu, you can hide it from mobile and tablet so it’s only visible in desktop and laptop, and you can hide your modal/collapse menu from desktop so it’s only visible on tablets and mobile.
If you’ve done these but still won’t work then please provide your site’s URL and we’ll check.
Thanks!