Norton keeps dropping off Win7 Start Menu???

This is more of an annoyance than a problem but does anyone have any idea why my Norton shortcut on the (Win7) Start Menu keeps disappearing?  It doesn't always happen because of Microsoft Updates (set to manual) but sometimes it seems to be related.  I can go down to All Programs\Norton Internet Security\Norton Internet Security, select it again and 'Pin to Start Menu' but it will just eventually fall off like a tourist taking a selfie on a cliff. 

It used to be that the heading stayed (on the Start Menu) and I only lost the Drop Down menu but now the listing disappears completely. 

My Norton isn't affected.  It still runs just fine. 

Anyone have any clues why?