The bounty where you have to kill 3 walkers is bugged for me, I killed one walker in the devils lair it registered, then I killed another one during a public event on the moon and it registered too, that's 2/3. Then I killed one in a public event on earth and it didn't register, now I tried killing one in devils lair again and that didn't register either. I can only conclude that the bounty is bugged somehow, please fix it.