When this issue occurs, the LyncIntFeature application pool or the LyncExtFeature application pool may consume more than the usual amounts of memory and CPU resources on at least one Microsoft Lync Server 2013 front-end server. Users who are homed on the front-end server may experience a delay on various operations, such as joining an online meeting, starting Lync Web App and expanding a distribution list.
Additionally, multiple events (event ID 3, event ID 28, and event ID 5013) are logged in the Application log and the System log on the Lync Server 2013 front-end server. For more information about these events, go to Events Information
in the "More Information" section.