Ubuntu hosts are not showing last reported

Problem:
Out of the 3000 devices we are having half of them not showing last reported.
But when you run puppet agent -t it all seems to work but won’t show the last report. I have cross-referenced with hosts that do show the reports and can’t work out why.

Expected outcome:

I expect to see the last report.

Foreman and Proxy versions:
Version
2.5.4
Active features
Logs
Puppet
Puppet CA
Registration

Anyone has any ideas pls