Problem with dropdown menu sub-sub-menu in Studio theme child - Gap

I have Studio theme installed. The top navigation menu operates as a multiple drop down, with sub menus and sub-sub menus. See screenshot.

All works OK from the homepage - see first screenshot. There is no gap between (eg) the "Account" sub menu and the corresponding sub-sub menu showing "Login" and "Register".

However, on every other page, other than the homepage, it shows as in the second screenshot, where I have drawn in a red arrow to highlight a gap that is occuring between the sub menu and the sub-sub menu.

Because of this gap, when the mouse is moved across to the right, trying to reach the sub-sub menu for "Login" or "Register", the sub-sub menu disappears because the site is understanding this gap as a user browsing off and away from the menu, so it disappears.

I am guessing others using Studio have this same problem? How can the gap be removed?

Alternatively, I read somewhere about adding a script or code to make navigation menus stay and fade eg for 3 seconds after onhover is gone, so after the mouse if removed from being over the menu, the menu still stays and shows for 3 seconds after.

Any ideas on the code to do this?