This bug is found on devices that have a 64-bit processor (A7, A8, A8X, A9 and A9X) and running iOS 8 or above. As for devices with 32-bit processors, remains safe.
So far it is not known why it happened. But according to some observers, the likelihood of confusion after the set to a different time zone so it made an error. Apple itself has not responded to this. It is not known how to overcome these problems.
But a user to report the device back to normal after 5 hours silenced. Those that claim to successfully return to normal after replacing the SIM Card. Problems on the clock settings in iOS is actually not the first case that occurred. Previously a number of users reported problems after device change their time zone from Beijing to New York.
We wait for a response from Apple. Hopefully, the problem setting the clock in iOS can be fixed.