I FINALLY figured this out after playing with it for FAR too long. Hopefully this helps somebody else.
if you are using superfish, the culprit is the following css [code] .nav li:hover, .nav li.sfHover, .nav a:focus, .nav a:hover, .nav a:active { background:#CFDEFF; } [/code] adding z-index: 1; to this causes the subsequent navs to end up below any menu.