Assume a time skew exists between a Microsoft Office Communications Server 2007 R2, Group Chat server and a Group Chat database. In this situation, the time that displays for all messages in the Group Chat client is incorrect. Additionally, if the time skew exists when the Channel service is started, the time skew is doubled in the Group Chat client.
This issue occurs because the algorithm that is used to compensate the time skew is incorrect.
To resolve this issue, install the following cumulative update:
2491973 Update package for Office Communications Server 2007 R2 Group Chat server: March, 2011
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.