Whenever you get the same item multiple times after a match, you can only dismantle 1 in the end of game menu (the others cannot be selected after dismantling one), and if you do all duplicte items are gone as well. If you do not, only one shows up in your inventory. Had this happen with 2x and 3x duplicates, 1x with 4. Now why do we get 3 or 4 duplicates to start off with, and second, good luck fixing on yet another broken item "soon".