Dropdown menu quirks in Safari

The "About" and "Download" dropdown menus (at least I can reproduce this issue on these two) go nuts in Safari, if you place your mouse somewhere where those menus would be when expended and you refresh the page the menu gets loaded exposed and doesn't collapse. If you hover over the "About" link the menu will actually collapse but when moving away it expends again. So it looks like that the javascript gets flipped somehow when doing this.
The only way to get rid of it is by moving the mouse and refreshing the page, though when normally navigating the site this is quite annoying as it happens quite often that your mouse turns out to be in this location after clicking a link.

I don't recall that there has been a safari update recently which might have triggered this.