Overachiever achievement bug

Anyone know if I’m missing something? I just finished the maw’s par score achievement on halo ce. That takes care of all the par score achievements, yet for some reason the overachiever achievement for doing them all went to 98%, and didn’t unlock. Not quite sure where the other 2% would be or if the game is just bugged?

You’re at 83% for Headstrong which is to beat the par score on Keyes. Try beating the par score for Keyes again and I’m confident that Overachiever will unlock.