Time drift occurs when the internal clock of a computer is not properly synchronized, often leading to discrepancies like being an hour behind. In this case, the workstation is the only device affected, indicating that it's likely a local issue. Time drift can happen if the system clock isn't syncing properly with an NTP (Network Time Protocol) server or if automatic daylight savings adjustments aren't enabled. It's less likely to be a CMOS battery issue since the technician has already verified the correct date and the system clock isn't completely reset (which is what happens when the CMOS battery fails).
References:
Troubleshooting Time Synchronization Issues in Windows (Help Desk Geek) (Zendesk)