Yo, I'm the blurred out person in that screenshot
The "oddity" is that this is the only container type item (that I know of) which rolls its items on being opened, rather than on being picked up.
Full rundown: I picked up all of the boxes on my DH. I sent them to my priest for unlocking (got JC just to be able to use the lockpicks). I accidentally opened/looted one on my priest and it contained a cloth item. I mailed the other 6 (unlocked, but not yet opened) to my DH, and all of these 6 boxes contained leather items.
I didn't mail a box I already checked the contents of or anything weird like that. All I've determined is that the loot is rolled when you actually open one, and the armor type is chosen
for the character opening it. I guess it's the same process that happens with item level, as others who have tried opening them on 101 characters pointed out. (Don't open them on 101 characters - you will get lower item level loot and can't get 810s.)
My theory was that a similar rule would be applied to relic types, i.e. you could only loot what you can use. I've since been told that it's wrong, as people have been getting holy relics on rogues (they have no holy relic slots in any of their 3 specs).
But regardless, loot being rolled
for the character opening a box is a noteworthy feature. I'd imagine that internally, the game auto completes a quest or something along those lines.
P.S.
Posting on an account from year 2009. Waddup