When dealing with hardware or software inventory issues, you man want to take a peek into the xml file generated during the inventory process. To achieve this, you need to create in %systemroot%\ccm\inventory\temp an empty file:
archive_reports.sms
Generally its path should be C:\WINDOWS\CCM\Inventory\temp.
This XML file can reveal what the last scan discovered regardless whether the scan was a full scan or a delta scan. For example, if find one piece of information missing in the hardware inventory you can get the hardware inventory XML file whose name is similar to 0eeda138-3fce-4d01-a1b3-f9aeec6782bd.xml and take a close examination for clues.
SCCM Monde 