Hi,
I have enabled the option "Display Submenu on -> Click" in the settings of the "Menu" Element.
I have multiple mega menus assigned as submenus to the elements of the menu and when I open one and afterwards another, the second one overlays the first one, without closing it first. See screenshot.
The link to my site is dentina.cloud/wwwind and you can test it by opening the "Spot" and "About" submenus or the "Browse Activities".
Thanks