I took the Void Feast Guardian Games Daily bounty, I have never really used Devour before but the bounty only says to defeat enemies with devour in streaks of 10. I had the devour effect up constantly through the entire duration of an "enemies are fighting among each other" event killing numerous enemies and yet it did not count at all. I killed alot more than 10 enemies and not once did the devour effect end, but I got nothing for it. If it is just from the melee ability itself then the bounty is impossible to get because you cannot kill 10 enemies in a row using melee because the melee ability does not recharge fast enough for that.