I defeated Mira twice without the achievement unlocking. It was the Frontier map.
Was this on hard/master and without mutators?
Yes to both. I just killed Zeam on the same map/setting, it triggered the achievement.
Is there a way to confirm it's on hard?
You select the difficulty in the skirmish menu. If she's set to hard this should be awarded.
I'll pass this through for review but it might be worth doing again yourself just to confirm it was on hard.
Difficulty and Personality can be set in the skirmish menu
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