It's because the time on your computer is set to West Coast time. When you connect your Bold to your comp, the Bold's time is updated. Just fix your time zone and time on your computer and you'll be fine.
Options > Date/Time. Set it to the correct time zone, and set your phone to Network time (stupid but I had to do both for it to work). Once you've set it to pick up Network time, hit the berry button and tell it to update time. Hoepfully this helps.
Posted from my CrackBerry at wapforums.crackberry.com