Its been changed to a group chat so its using the group chat name, this means there is either 1 member, or 3+. Make sure that when you remove a member you add another one, and if you add another one you remove the original one. If you shift+o for the console (this causes a rollback so make sure you click to advance dialogue once before you do) and type conversation_name['members'] (obv replace conversation_name with what its actually called) then it will print the members out for you, and you can check.