Achievement Glitch?

[Dorkon]

So I have all the achievements for l4d2 except the mutation one of course. but when i look at my achievement it says 1195gpts 58 out of 60. When i look to see which achievements i have and don't, it only lists the mutations one. has anyone else seen this or no what to do?

[Dorkon]

I checked the achievements on xbox.com and it says i have all except that one. But when i checked my total gamerscore it shows it at 31,855 when my xbox shows it at 31,915... i dont no which one is correct.

[nickinbinary]

common problem with many games just recover you gamertag