The game has spawned a "layered tee" non-playable apparel as the classic green apparel package in the world which I could pick up, but not see in my inventory. It did not count towards my total apparel items carried. I only found out that it is non-playable (crowd apparel) by searching the name in the console.
Sadly I cannot provide the ID for it, as the game has 3 or even more items of the same name. If my memory serves me right, it spawned in the PROC location that was called something along the lines of "Fueling Outpost", or "Refueling station". Sorry I cannot recall it precisely. It was in a room that seemed like an armory, alongside a few other apparel packages, loose ammo, and ammo boxes.
Just check where the said apparel "is used in", and remove it from loot tables that are not related to crowd NPCs. Alternatively, it could be a missing or wrong keyword on the item as well.