It's probably worth mentioning that a disconnected EAP will not be reset to factory defaults if you forget it while it's still disconnected. The username/password of the EAP assigned by the controller will still be in place if they re-connect, so you have to enter it again if adopting. To keep settings in sync, I would recommend to just re-connect the EAPs. If they are becoming disconnected all at once, almost certainly the link between the EAPs and the server running the controller had been lost.