Why is agent chat session duration timer showing an offset?

Environment:  

Chat / Agent console
Oracle B2C Service

Resolution:

The first step to resolving this is to have an affected agent step through the following:
1. Log out of chat and the Oracle B2C Service application

2. Confirm the Windows system clock on their workstation is accurate.
- This can be done by comparing to an atomic clock or searching your local city at http://www.timeanddate.com/worldclock/
- Update the time on the workstation exactly (down to the second)

3. Once the system clock is set correctly, have the agent login to CX and chat

4. Accept a chat session and monitor the duration time

Another scenario that can happen is that, after using the steps above, the duration is corrected, but eventually the duration becomes off again. Based on that, it is likely a problem with the workstation's CMOS battery which is used to keep time.  If the battery is almost out of power then the system clock could lose time.  

NOTE: If that is the case, a change in functionality in versions February 2011 and later will ensure an incorrect system clock does not affect chat durations for agents.

Notes:

In versions prior to February 2011, the duration was being calculated using the difference between the start time (sent from the chat server) and the current time (defined by the system clock).  If the two clocks are out of sync, the duration will be incorrect based on that difference.  Adjusting the system clock will correct this behavior.  This functionality has changed and now both the start time and end time come from the system clock.

Additionally, an incorrect duration will not affect any reports used for evaluating agent performance.  This particular timer only shows while the agent is working the chat.  It is for their convenience and does not impact statistics.  Once the chat is closed, the duration is calculated using time stamps that were recorded by the server.