I've noticed a wrong time setting every time I'm booting in Boot Camp. One possible solution to avoid this issue is to automatically set the date and time at every Mac OS X login. To do that, you can set "Users Deamons" in Lingon to send ntpdate -u.
Please post if you have a better solution...
Mac OS X Hints
http://hints.macworld.com/article.php?story=20070507030228844