A jQuery fix for the Divi Theme mobile menu that collapses all of the submenus

divi_mobile_menu_fix.css

.et_mobile_menu .menu-item-has-children > a {
	background-color: transparent;
}

#main-header .et_mobile_menu li ul.sub-menu.hide {
	display: none !important;
	visibility: hidden !important;
	transition: all 1.5s ease-in-out;
}

#main-header .et_mobile_menu li ul.sub-menu.visible {
	display: block !important;
	visibility: visible !important;
}

.et_mobile_menu .menu-item-has-children > a:after {
  content: '';
  width: 0;
  height: 0;
  border-left: 7px solid transparent;
  border-right: 7px solid transparent;
  border-top: 7px solid #ffffff;
	position: absolute;
  right: 25px;
}

.et_mobile_menu .menu-item-has-children > a:hover:after {
	border-top: 7px solid #cc0000;
}

divi_mobile_menu_fix.js

<script>
(function($) {
     
    function setup_collapsible_submenus() {
        var $menu = $('#mobile_menu'),
            top_level_link = '.menu-item-has-children > a';
        $menu.find('a').each(function() {
            $(this).off('click');
             
            if ( $(this).is(top_level_link) ) {
                $(this).attr('href', '#');
                $(this).next('.sub-menu').addClass('hide');
            }
             
            if ( ! $(this).siblings('.sub-menu').length ) {
                $(this).on('click', function(event) {
                    $(this).parents('.mobile_nav').trigger('click');
                });
            } else {
                $(this).on('click', function(event) {
                    event.preventDefault();
                    $(this).next('.sub-menu').toggleClass('visible');
                });
            }
        });
    }
     
    $(window).load(function() {
        setTimeout(function() {
            setup_collapsible_submenus();
        }, 700);
    });
})(jQuery);
</script>