Hello,
we have found out that Foreman 1.8 with Discovery 3.0 plugin does not
properly import discovered hosts facts when
'ignore_puppet_facts_for_provisioning' is set to true.
We will fix this and likely backport into 3.0.1 release sometimes next
week. Until then, disable this flag if you want to use Discovery.
I would like to thank Rob Greenwood for helping to track down this.