NodeIDs in EntityPhysical table not in NCM Nodes table

I have the strangest problem... 

Working with some Dell switches.  Pulling fields into a report - data lives in the NCM.EntityPhysical table.  Report includes device name which comes from the NCM.Nodes table..

The report returns, however, only about 80% of my devices.  The remaining 20% (approx.) do not appear in the report.

Drilling down using SWQL Studio.  Both the NCM.Nodes and NCM.EntityPhysical table include a field called 'NodeID' with a GUID data type.  Filtering the EntityPhysical table on 'Chassis' also trying 'Container" with 'Fan' Something so I get only one line per device.

For the missing devices the NodeID in the EntityPhysical table does not have a corresponding NodeID field entry in the NCM.Nodes table.  

Troubleshooting... attempting to find a fix action.

Does anyone in the community have an idea why there would be entities in the NCM.EntityPhysical table with no corresponding entry in the NCM.Nodes table?  Or... can anyone think of a workaround for this issue?  I need all of my devices to show up in the report with device name, and I need the fields from EntityPhysical.

Thanks!