Do you have VSE installed on the machine?
Kindly create a VSE deploytment task for new systems as well as deploy the McAfee agent one the product as well as agent deployed successfully to the new systems then the DAT and engine versions will be available in ePO console.
This is long standing problem. Machines with VSE installed will occassionaly report in that they have no DAT nor report an engine version. Sometimes if one redeploys the engine they will recover. Sometime reinstall the MA works. Seems to happen more often on low end, old machines.
But the issue has been around for years.
Pushing another install of VSE seemed to fix the issue.