Simply - upgraded boxes do not register any item (inc. loot case only award) as owned, so not as duplicate. Therefore will give any item over and over, without even the duplicate chips % of valuereward.
Regular cases register items as duplicate.
Xbox (old Xbox One)
I got him to send the log to you at 2020 UK time. (just after I did one, too)
Cheers Mayor - bust u l8r.