New Taxonomy Categories/Terms not showing


I am running a multisite installation. On the main site I have a custom post type set up as: 'ecp_products', with a hierarchial taxonomy: 'ecp_product_type' which works fine.

However, I have exactly the same configuration for a sub-site on the network yet when I add a new category under 'ecp_product_type' it saves and then disappears! By this I mean that I create and save the new category, but when I go back to the page the list is empty.