When adding a new user store, there is an option to Copy Settings From: an existing user store. In some cases, only the first connection from the existing User Store is copied over. All other connections, that are usually added for LDAP redundancy, are not copied.
This is working as designed. This was intentionally implemented this way in order to facilitate the ability to edit the connection information while setting up the new user store. If the copy did include all of the connections, then it would prevent the administrator from editing any of the connection information.