Assignee LOV query return no values

 Service security is enabled in our environment.I can select from a list of resources to assign a task on the service request form (CSXSRISR). But when I use the same query used by that LOV in another field, the list is empty. Any ideas why?

This is the query used by the LOV:

SELECT   resource_name, resource_id, resource_number, support_site_id,

         'RS_EMPLOYEE' resource_type, source_business_grp_id

    FROM cs_jtf_rs_resource_extns_sec

   WHERE TRUNC (SYSDATE) BETWEEN NVL (TRUNC (start_date_active),TRUNC (SYSDATE))

     AND NVL (TRUNC (end_date_active), TRUNC (SYSDATE))

     AND category = 'EMPLOYEE'