I'm running Elastic, Beats and Kibana version 7.5.2.
In SIEM under the "All Hosts" tabs the servers are listed but the Operating System and Version is showing as a dash (-).
If I drill into the server it gives me a breakdown of the server in which case the Operating System is correctly showing as "Centos Linux" with version showing as "7 (Core)". If I mouse over these it shows "host.os.name" and "host.os.version"
The fact that the data populates in one view, but not another suggests to me it's a bug. Is this working correctly for other people?