Plural and Singular Post Title Fields Remain Empty

I have a custom post type that I created. After working with it for a bit (adding relationships and custom fields), I noticed that the entry shows up as (no title) on the list of custom post types. The Plural and Singular fields are now empty, while the slug looks normal. There is no major impact on functionality, and updating the fields seems to update them appropriately elsewhere on the backend (but they continue to appear empty on the MB interface).