I achieved the appropiate rating for the “Duelist” Achievement listed under PlayerVsPlayer> Arena in the 2v2 Arena bracket but I have not gotten the achievement. Currently I am at 2100+ rating. I submitted a support ticket and GM Adwarmor stated this is a unqiue bug and that I should report this issue here.
You might need to win a game while at the rating for the achievement to trigger
Tried that. It doesnt work. My arena partner, who is having the same issue, is at 2130+ rating and no achievement.