If you have the normal version disc of the game and this achievement glitched on you don't worry just keep leveling up until you max out your level on level 50.
Then go to dashboard then storage device or memory unite and go to Crysis 2 file and delete the title update, Go back to the game and download the update.
Now go to multiplayer and reboot your suite if the achievement doesn't pop after the reboot go and play 1 full game on CTR and the achievement should unlock by the end of the game.