Hi. Are you wanting to use the CSS from the theme for your menu rather than from the plugin? There is an option in the admin page for the plugin to control that (you can only see it when you using a theme designed for it).
The CSS being used at the moment is from the plugin and is display as I’d expect it to. You are using two menus and since there is no CSS added to your second menu it is displaying as an unstyled list of links.
It is possible you don’t have an option in your admin page if you did not set the menus to be dropdowns in the template generator.
Hopefully that makes sense. If not, let me know and I’ll try to explain better.