Article ID: 2501085 - View products that this article applies to.
Consider the following scenario:
This issue occurs because the Channel service caches a time skew value when it starts, and then uses this value during the whole session. This time skew value is added to all the messages that the Group Chat server sends to the Group Chat client.
Note The value of the time skew is based on the time difference between the Group Chat server and the Group Chat database.
To resolve this issue, install the following cumulative update:
(http://support.microsoft.com/kb/2500447/ )Description of the update for Lync Server 2010 Group Chat: April 2011
To work around this issue, restart the Channel service after you correct the time on the Group Chat server.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.