I have two demo pages here:
http://quiltersrule.com/beta/index.html
http://quiltersrule.com/beta/retail.html
When hovering over "Instructions & Products" as well as "Events", the last child link does not have a full background until you hover over it. The "About Us" is just fine. I have tried messing around with z-index, but this does not seem to be the problem. I have no idea what to do.
All the code and everything should be accessible via View Page Source so I'm not going to try to paste it here.
Edit: Forgot to mention this happens in IE only. Sorry!
UPDATE: If the issue is only in IE, then an IE specific stylesheet is what you need:
<!--[if IE]>
<link rel="stylesheet" type="text/css" href="all-ie-only.css" />
<![endif]-->
Original:
Looks fine to me (Chrome v27, OS X 10.8):