(This is related to thread  http://www.geekzone.co.nz/forums.asp?forumid=85&topicid=59375&page_no=1 )

HTC Touch Diamond2 T5362 Win Mobile Prof 6.5.1 TouchFLO 3D 2.1

‘phone was set to “GMT +12 New Zealand”
Settings > Personal  > Phone | Time Zones “Automatic change time zone and clock” ticked.

At the end of NZ DST 3am this morning the ‘phone changed time to 2am, however later in the morning the clock had jumped ahead by 1 hour again. It seems this was related to the time zone/clock update service that Telecom XT network provides. I was able to verify this by turning Settings > Communications > Phone to “Off” then backing up to 2:58 am today and allowing the DST transition to repeat. The ‘phone then retained the correct time (ie did not jump ahead again) even after turning the ‘phone itself off/on.  Also, turning “Automatic change time zone and clock” off seemed to prevent the problem, however that loses the advantage of XT’s provision of time updates. (I tried turning HTC TouchFLO 3D off, but this did not seem to solve the problem on my TD2.)

A workaround described by STACKORAMA  in
http://community.htc.com/na/htc-forums/windows-phone/f/33/t/436.aspx?PageIndex=1  seems to be related to a similar problem which arose years ago when installing MS time zone updates. That is, after the DST change, (with Settings > Personal  > Phone | Time Zones “Automatic change time zone and clock” ticked) and before the ‘phone picks up XT network time, manually change the time zone to (say) Tonga, then switch ‘phone off/on to force a time zone & clock update from XT. Afterwards the time zone showed as “GMT +12 New Zealand”, the clock time was correct, and remains correct through further ‘phone off/on cycles.

I guess experience has taught us that we cannot expect the developers of MS Windows Mobile - HTC TouchFLO 3D to do quality control to prevent the repeat of past failure scenarios, or even maybe provide timely corrective downloads.