OpenURL setups are stored in the library table, with the institution name and OpenURL. When a user selects a library in their settings, the OpenURL is copied to their profile, in the user_data column (stored in the link_server key in the JSON blob) in the users table. If the OpenURL is updated in the library table, the corresponding URL in the users table is not updated, so the users are directed to the stale URL. This currently requires a SQL update directly to the table.
Ideally, the database schema would be adjusted so the URL itself isn't stored in user profiles, but a pointer to the correct item in the library table is stored instead.