My little brother picked this up recently and was playing this morning. As he got his eleventh achievement the game froze, he waited two minutes and then decided to just turn the console off and on again. When he got back online he was up to fifty achievements.
So it unlocked forty achievements at once! Including some for online play and Euro 2012. He has neither an online pass nor the DLC, we have absolutely no idea what triggered it sadly or I would share with you all.