From #12392, Dmitri says:

It might be possible to set some flag indicating that fact import is in progress, but it's going to be messy.

When saving hosts during fact/report importing we use .save(:validate => false) - not really in an attempt to disable validation, but to disable orchestration (as I understand it). The same isn't done for saving network interfaces, and now that orchestration's in those models, it's running.

If we had a flag to disable orchestration generally instead of disabling validation, we might be able to keep validation on NICs (something we really shouldn't go backwards on by disabling) while disabling orchestration changes at a high level?

setting ignore_puppet_facts_for_provisioning to true resolved this issue for us.

https://github.com/theforeman/foreman/commit/4c9529c7bc3c081fb3d0bfdbee09b2e7d6eabc0a#diff-5e596b03372d6df756203e6c69444742

Makes this worse as Foreman now does two calls to smart-proxy during fact import effectively doubling the load.

If you are using ISC dhcpd, I would suggest testing import against changes in https://github.com/theforeman/smart-proxy/pull/409, calls to smart-proxy's dhcp module (when used with ISC dhcpd) no longer incur heavy penalty.

Oh I take it back, it resolves the issue.