Level 2 submenus disappear

The site uses the theme Associates and its navbar. When you click a top level menu the drop down menu appears but if you move the mouse from the drop down to a third level the side menus disappear & you cannot get at them. This behaviour seems to be predominantly via Chrome but I have seen it occasionally on other people's IE.
There is a post where this was solved by decreasing the vertical separation but the setting for VS here is zero so cannot be decreased.
Any ideas please?
td

The website is at HERE and the problem occurs when you go Enrolments & Programs > Timetables > Weekly

Seems to function fine in all latest version browsers here.
But if the mouse cursor does slip outside the boundary it will disappear, maybe increase the font size which will enlarge the active area.

I notice the same behavior, also with the other sub-menus, when using Chrome. When I keep on trying and move the cursor very slowly and carefully sometimes I manage to select the sub-menu items, most often I don't. Using IE9 I don't have this problem.

Using Chrome Version 24.0.1312.57 m here.
Not getting any different behaviour than other browsers.

Same version of Chrome here and tried it on both a desktop running XP and a laptop running W7. I notice a clear difference between Chrome and IE.

Just had the same problem and it didn't seem to be browser specific. Nor was it consistent. But the way I cured it was to increase the size of the border - which of course you can make the same colour as the background if you actually don't want a border. This is under Navigation Bar Properties and then Pop up menu style...

No difference in any browsers at all.