Ouroboros gun sticker unavailable after Gauntlet Tier One Operator 5 completed

Ouroboros (Gauntlet Tier One Operator Challenge 5 reward) weapon sticker will not unlock.

In Loadouts → Select Sticker → Ranked, the tile is locked and shows “Currently Unavailable.” The weapon preview can temporarily show the multi card art on the gun, but the sticker cannot be equipped.

Challenge 5 shows complete. Restart, extra matches, and rechecking Challenges / Loadouts did not grant it.

Reproduced on Xbox Series X, PS5, and PC.

Related: https://forums.ea.com/idea/battlefield-6-bug-reports-en/ouroboros-stickers-missing---challenge-5-completed/13588656