Think that's a blizzard issue?
http://us.battle.net/wow/en/forum/topic/6521202863#1
Anyways, try
http://www.wowinterface.com/forums/s...ad.php?t=21199
/nui clock {local|server|both}
This option sets the display of the dashboard clock to either display the current local time {local}, the current server time {server} or both the server and local time together {both}. The default setting is {server}