Consider the following scenario:
- You deploy the Response Group Service (RGS) in a Microsoft Lync Server 2013 environment.
- You configure an RGS queue, enable queue overflow, and configure the queue overflow call action.
- Users call the RGS.
- The RGS transfers the incoming calls to agents.
- The queue overflow threshold is not met.
The issue occurs because of a race condition in RGS. When the race condition occurs, a call that is successfully handled by the RGS is not deleted from the database. When multiple calls are not deleted, the queue overflow threshold can be exceeded. Therefore, the queue overflow call action is triggered.
To resolve this issue, install the cumulative update that is described in the following article in the Microsoft Knowledge Base:
2835438 Description of the cumulative update 5.0.8308.420 for Lync Server 2013, UCMA 3.0 Workflow APIs: July 2013