The Address Book UI people picker has been changed for iOS 8. A new mode with new API has been added where the app does not need access to the user’s contacts and the user will not be prompted for access. A temporary copy of the selected person is returned to the app. See ABPeoplePickerNavigationController.h for more details.
In iOS 8 beta 2, you must use the new mode. The old mode has been deprecated with this beta.
Another big move from Apple on the privacy front — the new Address Book UI people picker doesn’t give full access to contacts to apps. Instead, users only share a single contact with the app. Apple seems to be using iOS 8 to establish itself as the internet and technology company that cares about user privacy.