duplication bug

i had on my gear when i prestiged.. specifically 3 no lvl req purples and 1 heirloom, had others but they didn’t dupe. when i prestiged it didn’t remove the armor. when i went to the mailbox and grabed my gear and went to put it on i relized i had double of my heirloom, epic helm, epic belt. upon closing the game and relogging the belt on my character was still there as well as the one in the mailbox, but the duped helmet and heirloom was gone. the helm i was where was gone but the one in my bags was still there and the heirloom that was in the bag was gone but the one i was wearing was still there. I deleted the dupped belt from the mail and no other dupped items on on my charactor. i could not take a screenshot because my game kept crashed when i tried and after that the dupped items were gone except the one in the mailbox but i couldn’t get a pic of it