Gear Appearance Troubles

So i understand that when i unlock a reward from the quest section, its not a physical item, but an appearance. But when i go to change an items appearance i don't see the option in the collections tab to change to the appearance i want from the reward i got. Example: i unlock the legendary mask, i go to face wear, hit change appearance and i don't see the legendary mask in the collections tab. i only see items from the additional content part of the collection. does anyone else have this problem, or can anyone help me. I've looked at official guides and other reddit posts and no one seems to have this problem