Call of Duty: Black Ops 4 now has duplicated protected loot boxes.
Dupe-protected crates, as they’re called in-game, were added to the Black Market yesterday, 1st July. They contain three duplicate-protected items from the reserves pool, but you’re protected against getting duplicates.
Black Ops 4’s standard loot boxes have a chance of spitting out a duplicate item, much to the annoyance of players. With standard loot boxes, if you get three duplicates, you get a re-roll.