Symptoms
When you receive a call from a private branch exchange (PBX) user for the first time in Microsoft Lync 2013, the P-ASSERTED-IDENTITY header field in the INVITE request contains the caller's display name.
Note This issue does not reproduce when you receive the next call from the same telephone number. However, this issue reproduces after you restart Lync 2013.Resolution
To resolve this issue, install the following updates: