Beating DC on E doesn't count toward achievement?

[KillerKrieg]

I have experienced something strange in achievements. The first campaign I beat on expert was was Dead Center. Sometime after that, I looked at the achievement Still got something to prove, and it said 0/5. Now, I figured that even though I don't remember dying in this playthrough, I must've, and that must be why it didn't count. However, when I beat Dark Carnival on expert I found this is not the way it works(1/5 now). The game doesn't care if you had a perfect run or how many times you died as long as you live through the finale. So with that said, why is it not 2/5? Why would Dead Center not count toward this achievement? Is it not one of the original 5 scenarios of L4D2?? (According to my Xbox360 copy of the game, it is) And, if it doesn't count, then which scenario actually DOES count in it's place?

[Munkee]

the achievements can glitch. same thing will happen for mutations.
I noticed sometimes they appear later, sometimes they have to be redone.

[KiRA (BLZ)]

I remember me getting it and my brother didnt get Hard Rain on expert and was quite pissed,so yeah sometimes this game mocks you.

[Ninjabutter]

Yep, sometimes the achievements bug out just to mess with you. I had it happen with two of the campaigns for that achievement.

[Munkee]

i guess if you beat it without a problem, the game gets offended and thinks (do it again Puta(if spelled right)..)

[buddy]

or it may not appear until you exit steam and restart it; and steam updates can cause all manner of chaos, so that's just another couple of considerations

[☺ Will Longstaff the Clockwork]

Oh no! What a tragedy! Hhahaaa!