Symptoms
This issue occurs when the Response Group Service (RGS) queue has only one agent and Attendant routing method is not selected in the Microsoft Lync Server 2013 environment. The calls may be from either Lync users or public switch telephone network (PSTN) users.
When the agent accepts the first waiting call, the agent just exits a call with a user who called into the RGS queue earlier.
Cause
This issue occurs because the RGS server incorrectly treats the agent status as "Available" when the agent is talking with the first caller.
Resolution
To resolve this issue, install the February 2015 Cumulative Update for Lync Server 2013 Response Group Service.
