[Replicant]

This should do it(Tested on 5.2.2). The class b_menu__dropdown--active only highlights the button for the drop down login. This code shows the login box for 8 seconds give or take, but I'd suspect the timeout needs to be a little longer to give the user time to react.

<script type="text/javascript">
$(document).ready(function() {
  $(".js-menu__dropdown-submenu.b-menu__dropdown-submenu").css("display","block");

 
    setTimeout(function(){$(".js-menu__dropdown-submenu.b-menu__dropdown-submenu").css("display","none");console.log("Dropdown Timed Out")}, 8000);
}
);

</script>