I've seen it a lot, that when someone closes a role to prevent people auditioning, that it's automatically assigned to a mysterious "offsite actor". Most times I've seen this, this hasn't actually been the case - they're just taking time to think over the casting call. Instead, it should simply be marked "closed", and if it is indeed a role that has been cast to an offsite actor, have a checkbox for that. It should also prompt you to select someone in case you have forgotten, but not force you.