The one hour difference makes me think that it might be a daylight saving time issue, eg on the east side of Australia we have timezones AEST (Australian Eastern Standard Time) and AEDT (Australian Eastern Daylight Time) and sometimes they are in synch (winter) and sometimes they are an hour apart (summer).
AEST is for the northern states close to the equator, which have daylight hours that don't change much and thus daylight saving is not of practical benefit* and not used.
AEDT is for the southern states away from the equator, which have significantly fewer daylight hours in winter and more in summer, and daylight saving shifts the bonus summer daylight towards the evening.
When AEST and AEDT times are aligned (during winter), it is easy for somebody to choose the "wrong" timezone because both local times are the same. The usual scenario six months later when daylight saving starts, is that the device time is then an hour different (either because it didn't adjust for daylight saving when it should have, or did adjust when it shouldn't have) and the user "fixes" the problem by turning off auto-time-synch and manually "correcting" the time.
My first check would be to synch the device time to an internet time server, and see if the device is then still showing correct local time. If it is not, then have a poke around in the device timezone selection/setting, looking for one that would correctly match UTC to local clock time.
* other than avoiding time differences esp. at state borders