Hello I have a ABPeoplePickerNavigationController, on creation is set its navigationBar hidden.
peoplePickerController.navigationBar.hidden = YES;
If you believe this is a bug you should submit it to http://bugreporter.apple.com.
To me it also sounds like a bug, but I'd double-check with the documentation to make sure. If it doesn't mention anything, then I suggest reporting the bug.
Edit: On the other hand, I would think setting the navigation bar here to be hidden is a bad idea. Is there a particular reason for wanting to hide it?