The game is loading the LOD(Level of Detail) models, its a feature in-games to help optimize games since you wouldn't really need the high poly model when viewing from a distance.
to fix this for your mod though, open your hihead.SCNE file and go to the very bottom where it says "Object", then remove the entire LOD line here.

You are going to have to do so for the facialhair.scne facialhair_tangent.scne file for this also so it doesn't glitch out.