Hai~ :3
So this problem has been excruciatingly difficult to work with. I'm making a personal companion using CMCompanions. The NPC uses a shield, sword and cuirass from the Vanilla game; however the greaves, gauntlets, boots and helmet are all from a modded resource (The Knightly Armory pack)
When giving my companion these items in the Construction set, his preview will show him with them equipped. When I place him in the world however, these modded armors magically disappear. When I check his inventory after, it seems all but the vanilla items have been removed. This persists in-game aswell. I've tried to place him, re-equipped his armor and save the .esp, but in-game his armor has disappeared.
I'm not even given a warning message for this, it's just disappearing right under my nose!