I got a queenbreakers' bow doing Challenge of the elders yesterday,except the thing is that it won't tell u that u got it when u get to the rewards screen or before that,u actually have to check your inventory to see if u got a Poe exotic,I didnt even know I got my queenbreakers' bow until I got to the tower and checked my special weapons inventory XD P.S I texted this in 2017 May,just saying :/ Also, I did COE 3 or 4 times after that and no luck,so the drop rate is kinda low,but I'm still waiting for my dregs promise :D