My HTC Hermes (AT&T 8525) keeps switching from the time and zone I set in Settings — in particular, from Singapore/Malaysia’s timezone to Ulaanbaatar’s. I found just one Google match about this problem: http://www.ppcsg.com/lofiversion/index.php/t93410.html, and it indicates the problem also affects the HTC Touch. The solution is to go into the Phone app, Menu, Options, find the Time Zones tab on the far lower right, and uncheck “Automatic change time zone and clock”.