Hey,
I released new FDI build 3.7.5 which aims to fix a regression after facter 4 upgrade in 3.7 series. Hosts with uninitialized NICs were not reported correctly.
http://downloads.theforeman.org/discovery/releases/latest/
https://projects.theforeman.org/issues/31943
Please update and report all regressions in the 3.7 series. Upgrading facter from 2.x to 4.x may cause more issues than just one.
Cheers!