A Battersea Compound mission glitched? ("Do A Barrel Roll")

[Zeitgeist-9]

Hello everyone, I was playing DiRT 3  a few moments ago and the when I was trying the "Do A Barrel Roll" mission (Zone 3, Powerstation), it didn't unlocked the achieve even after many tries, that could be one of my first missions completed, but I was playing since some days ago in a way to get the 100% on these days, when I was only 4 missions away to the 100%, that was one of them, time later I could complete 79 missions, but the same mission hadn't unlocked on that moment, I saw a video and  tried to do exactly the same (with the same car, angle, speed and acceleration from the one who made the video), it still didn't work, very disappointed I exit the game, but I thought to try one last time, it unlocked at the first (And with a diferent car from the video I saw), my version is the Complete Edition (North American version), maybe I will say that to me the way I could get that achieve and obviously the trophy was:

1. Complete all the other missions
2. Exit the game
3. Start again the game
4. Select your favorite car
5. don't change any car setting
6. Try only the remaining mission

I hope it will help anyone who has the same problem with that mission