Well, some of them anyway.
I have been running FCOM and a custom integration of my English OWCND 1.30, and have noticed a problem where if non-leveled list NPC's (like Angalmo in the Chorrol Mages' Guild for example) are assigned leveled list items in their inventory for their clothes, that the game engine will mysteriously fail to assign them on loading in-game.
It isn't that the NPC just doesn't equip the item. For some reason, leveled items are not added to non-leveled NPC's at all (can confirm by pickpocketing, killing and looting, etc.).
I am actually rather amazed that almost 10 years in there is so little discussion of this issue.
I am really hoping someone here can help!