Double check the node GUID and if the node has multiple NICs
By default, systems are first matched against an agent’s GUID. If this GUID doesn't exist, the McAfee ePO database uses attributes specified in the Rogue System Matching server settings. You can specify which attributes the database uses for matching, based on which attributes are unique in your environment.
If a system on your network has multiple NICs, each system interface can result in separate interface detection's. To eliminate duplicate systems use the Detected System Matching Server setting to match multiple interfaces to an existing detected system. You can also configure your server settings to automatically match detected systems with multiple NICs.