Completed 422 Unprocessable Entity during fact import

Issue

• We are seeing quite a number of 'Completed 422 Unprocessable Entity' errors during fact import.

2018-06-08 06:56:41 ae943b1d [app] [I] Started POST "/api/hosts/facts" for 127.0.0.1 at 2018-06-08 06:56:41 -0500
2018-06-08 06:56:41 ae943b1d [app] [I] Processing by Api::V2::HostsController#facts as JSON
2018-06-08 06:56:41 ae943b1d [app] [I]   Parameters: {"facts"=>"[FILTERED]", "name"=>"host.example.com", "certname"=>"host.example.com", "apiv"=>"v2", :host=>{"certname"=>"host.example.com", "name"=>"host.example.com"}}
2018-06-08 06:56:41 ae943b1d [app] [I] Current user: admin (administrator)
2018-06-08 06:56:41 ae943b1d [app] [I] Completed 422 Unprocessable Entity in 18ms (Views: 0.3ms | ActiveRecord: 2.2ms)