hehe, tricky topic. not a real dupe though. just read below
i was xfering some items from my NL chars to another for completing the builds. i was in a safe/private/pwd game and using window trade.
my assassin needed some items which i had on a mule. my sin had anni, torch and cube only, too much space was available. my mule had exactly 2bartucs, stormshield, verdungo, ravenfrost, eth gladiators, shadowdancers and a rare diadem. if you calculate the space needed it fits my sin's inventory so i thought i can put all items in screen and trade all at one time.
i put all items on window and clicked yes on both chars.
only big items are xfered to my sin (eth gladiators, stormshield, 2bartucs). but i could see all items were still on my mule char (including above ones).
i tried to exit game and reenter same and another game to see if it was a real dupe. nope, they vanished like they were never traded. i tried same thing again and same thing happened, duped.
i again tried xfering but smaller pieces this time. everything worked fine.
i forgot to drop the traded items on my sin to test so dont ask:(
something smells again, especially after the new patch. in the notes it said sth about fixing a dupe method. maybe they -blizzard- opened another hole. i xfered nearly 100 items from different chars tonight on NL but only happened on this char specially.
i just wanted to inform you because if this can be reproduced then it can be used as a trade scam.