Problem with the world model meshes of the Anatagonizer and Mechanist helmet. If you drop them on the floor it will show a big red exclamation point.
Edit: Figured out half of my problem, it was original meshes of the two helmets that came from FO3 as loose files. This would take precedence over TTW's own fixed mesh for the antagonizer mesh stored in the BSA. However, the Mechanist helmet is still bad.