All Inventory missing
Could be different reasons, like missing data or matching issues.
Are you running FNMS on-premises? In this case you could check the database, e.g.:
SELECT * FROM ComplianceComputerConnection
I wonder if the raw computer details have been normalized or merged in some way to give the 905 inventory device records.
Looking at information shown on the Discovery & Inventory > Inventory Device Matching page about the raw computer records that are imported and how they are mapped to inventory device records may give some insight here into what has been done.