Fixing Persistent Sub-menus

This simple fix will resolve a minor bug with the default Navigation block.

Copy and paste the code below in your CSS file.

/* fix persistent submenus */
li.wp-block-navigation-item.has-child.open-on-hover-click.wp-block-navigation-submenu > ul.wp-block-navigation__submenu-container.wp-block-navigation-submenu {
    display: none;
}

This code prevent sub-menus to appear after opening the link in a new tab.