A work round for where your sub menus in  Twenty fourteen secondary menu is not aligned, detached or overlaps.
If you have customised your 2014 secondary menu  and the sub or sub-sub menu doesnt’ work then add a style change in your twenty fourteen child’s CSS. Simply change the xxxpx width of  the CSS “class secondary-navigation ul ul” rule to whatever fixes the problem. Simpy use firebug or keep changing the setting until you get what works.

.secondary-navigation ul ul {
width:xxxpx;
}

Obviously

.secondary-navigation ul  {
width:xxxpx;
}

will set the WordPress twenty fourteen initial submenu width.