Average Logon Duration Is Not Available In Citrix Director

When an administrator logs in Citrix Director and goes to "trends" to look for Average Logon Duration, the information is not available. Logon Duration in MonitorData.Session Table in Monitoring Database also shows "Null" value for "Logon Duration" Restarting the Monitoring Service on Delivery...

Director does not show Logon Duration for all sessions

When viewing "Average Logon Duration" not all connections are visible...