About a week and a half ago, we realized that quite a few calendar events were an hour behind schedule inside of Outlook (Created for 5pm, changed to 6pm on the calendar). After testing and checking that everything had the proper time zones and DST adjustment settings, we found that it only happened when an item was created inside of Outlook (2003 or 2010, didn't matter) and accepted on a Mobile device (we tried iPhones 4 and 4s as well as a Droid phone). Anything created on a mobile device went through fine and any events created in Outlook were correct when they were accepted on another workstation through Outlook.
Keeping an eye on the events on our phones, we found that the time was correct on the event invite and only changed after the device reconnected with the server.
I've tried running updates, checking DST and time zone settings both in windows, on the server (server 2003) and on the phones. All are correctly set.