The Definition Date filter does not properly filter the Client Inventory Details report in the Symantec Endpoint Protection Manager (SEPM) console. Clients that should be removed from the report by this filter still show up in the report, but show Definition Date as Not Available (instead of the actual date they have). 

If the same report is run without this filter, all data shows in the report as expected.

This issue has been fixed in Symantec Endpoint Protection 12 Release Update 2 (RU2).  For information on how to obtain the latest build of Symantec Endpoint Protection, read TECH 103088: Obtaining an upgrade or update for Symantec Endpoint Protection or Symantec Network Access Control.