OE adds time to email

One of my users is using OE (Windows 2000). Whenever she sends a message it arrives with the correct time (ex. 1400 hrs), but if you reply or forward the message, it states that the sent time of the included original message is 61 minutes later (so, in this case, her message would be at 1501 hrs, not 1400 hrs as sent originally).
I’ve checked the laptop and can’t see anything myself that is amiss.
While this isn’t an earth-shattering problem it is problematic and if she starts sending time-sensitive documents it could be cause for alarm.
Any thoughts?