SharePoint not showing links under subsites(dropdown) on top link bar of home page

I have a home page with various sub sites showing on top link bar( of home page), problem is I all the links in all sub sites are not visible(dropdown appears white) SharePoint Server Publishing Infrastructure feature is activated and when I go to Site Settings > Navigation, all links are there in their correct subsites, even when I try to add a new link it doesn't appear.

Ticking show subsites and show pages does not seems to solve this problem. This though is working on my dev server(which mirrors the current affected production servers). Any ideas how I can make this pain go away?