I did the Metropolis City Hall duo and the Omac duo so I could get the Kabuki style chest. It didn't drop for either of the duos. I know that it should've dropped because I looked it up.
Maybe it was just bad luck? If it continuously doesn't drop then perhaps it was changed. I would keep trying. ;-)
You consider it unlucky to not get the exact drop you want on the first try...your playing the wrong game
i ran the duos for 5 months before i finished that set of gear... you need to re run it every day in hopes it drops...the t2 and t3 duos also drops that gear...its a very rare item
Ive deleted enough kabuki gear to make a good 3 or 4 complete sets from the t3 solo challanges. Run those if you can. I also noticed Necormancer gear from OPs reward boxes. Got a necromancer troller back piece. level 76 item. I felt trolled