hello
can I get your site link? we did not find issues on our testing platform and please mail us at amplethemes@gmail.com , we are happy if we help you
Go To customize > additional CSS and copy and paste below CSS and published it, let me know it works or not, if it does not work please mail us at amplathemes@gmail.com
ul li:hover > ul, ul li ul:hover {
visibility: visible;
opacity: 1;
display: block;
}