Manually added menu items aren't showed

I'm trying to add a few links to nodes to menu generated by taxonomy_menu. All works if I create them manually on menu edit page. But if I toggle a 'Provide a menu link' checkbox on a node creation page, after pressing 'Save' all links to nodes dissapear from a taxonomy menu block. Only after editing the menu, say reaarranging the order of menu items, they come back again.