A Public Switched Telephone Network (PSTN) user (user A) makes a call to a Lync 2010 user (user B). Then, user B forwards or transfers the call to another PSTN user (user C).In this situation, the call history on the Mediation server only shows the call from user A to user C. The call history does not show any information about user B.
To resolve this issue, install the following cumulative updates:
2500442 Description of the update for Lync Server 2010: April 2011
2502810 Description of the cumulative update for Lync Server 2010, Mediation Server: April 2011
Note After you apply these cumulative updates, Lync Server 2010 Front-end sends a Referred-By Header to Lync Server 2010 Mediation Server. To resolve this issue, install these cumulative updates together with the cumulative update described in Microsoft Knowledge Base (KB) article 255421.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.