Rogue current menu item class in wp_nav_menu()

Question

I am working on a 'from scratch' theme which has a simple wp_nav_menu call;

 wp_nav_menu(Array('menu_class' => 'nav', 'container' => FALSE)); 

On standard posts, archives and pages this produces the HTML I am expecting.

I have an issue when the active page/current menu item is a custom post type archive/single, wp_nav_menu generates the expected current-menu-item class for the active menu item, however it also generates a *current_page_parent* for the Blog link. The blog simply cannot be a page parent for a custom post type archive/single.

Some related images to help: http://bloke.org/uncategorized/untitled-post/

So how or why is this happening?

Answer 1

From look at core this is coming from this:

// back-compat with wp_page_menu: add "current_page_parent" to static home page link for any non-page query
if ( ! empty( $home_page_id ) && 'post_type' == $menu_item->type && empty( $wp_query->is_page ) && $home_page_id == $menu_item->object_id )
    $classes[] = 'current_page_parent';

It seems to be some legacy thing, I would just ignore it if you don't actually need it for some reason.