Ah yes, duping, it’s the one thing that has plagued the Diablo series for as long as I can remember. As of now trading in Diablo 4 has been suspended with a notice posted by Blizzard this evening alerting everyone to a duping exploit.
Duping Exploit Suspends Trading
We thank you for reporting this exploit to us and your patience.
This was also subsequently added:
Even though I am involved in game development, I don’t know the ins and outs of why this is such a problem in Diablo. It rears its head time and time again and it’s just such a pain in the backside.
Now, there are going to be people trying to take advantage of this but don’t. They will catch you and you will be penalised. Take that as a warning in case Blizzard’s current trading halt has not stalled the issue until trading is reenabled and the duping exploit fixed.