Consider the following scenario:
You set up a delegation in a Microsoft Lync Server 2013 environment.
The manager and admin are homed on different Front-End pools, Survivable Branch Appliance (SBA), or Survivable Branch Server (SBS).
The admin makes an outgoing call to an external contact on behalf of the manager.
In this scenario, the admin's phone number is sent to the external called party as the caller ID, instead of the manager's.
This issue occurs because the request that's agented by the Outbound Routing component of Lync Server 2013 includes the caller ID of the delegate instead of the manager's.
To fix this issue, install the July 2017 cumulative update 5.0.8308.992 for the Lync Server 2013, Front End Server and Edge Server.