OK, I think I have figured it out. I noticed on the device settings in Manage > Devices the mis-reported servers said on the RAC Device Information that the RAC Connection Status was off. I guess this device was being discovered through OMSA rather than the DRAC. I discovered the DRAC and the Manage > Devices show the RAC connection Status as on and the report shows the correct iDRAC FRMW version.
We have over 150 Dell servers in our domain and use OME (version 2.3.0.1721) to manage them. I want to use reports to view the firmware level that the iDRACs are. I have gone to Reports > Server Configuration > Server Components and Versions and exported All Devices as a csv. I can see inconsistencies with the results displayed here and if I view data from Manage > Devices >  Does something need refreshing, or data purging? Thanks in advance
Inaccurate OME Reports