Consider the following scenario:
A Group Chat server is deployed in a Microsoft Lync Server 2010 environment.
User A is a delegate of user B.
User A signs in to a Lync 2010 Group Chat client in the environment.
User A logs off from the client.
In this scenario, user A cannot perform actions as a delegate even though user A is displayed as a delegate in the account for user B.
To resolve this issue, install the following cumulative updates: