Apple has acknowledged a problem with some iPhone 8s, namely that they randomly restart, freeze up or won't turn on at all.Apple said it's a manufacturing defect and only affects a small percentage of the phones; Apple is offering repairs free of charge with some restrictions Consumers having trouble with their iPhones 8s can contact Apple Support to do a mail-in repair, or get an appointment at an Apple store.The announcement comes ahead of Apple's unveiling of the new iPhone 9 on Sept. 12.