Operations Manager has discarded %1 items in management group %2, which came from %3. These items have been discarded because ...

Operations Manager has discarded %1 items in management group %2, which came from %3.  These items have been discarded because no valid route exists at this time.  This can happen when new devices are added to the topology but the complete topology has not been distributed yet.  The discarded items will be regenerated.