Is there anybody at Activision that cares that can make a fix for the "There is no cake" achievement not unlocking. Played through this game three times redoing all achievements requirements with no early exiting. All to no avail, still don't have it. Super frustrating when you meet all requirements for an achievement and don't get it, especially when it is the last one you need to 100% a game on your gamer card. And the lack of a stats page to at least see where you might be missing something required for this in my opinion was a huge stumble for the programmers. Obviously the way your stats are tracked is glitchy. This game is broken and please don't use the "not enough demand for a fix" excuse.
This is an old thread but I too am having this problem and it's incredibly annoying. I have done everything that you have done too. Did you ever find a fix. Or better yet can Activision just give us an answer to this issue?
Sorry for the late reply.
Some users are reporting that by re-playing the MP achievements, the one you are missing should unlock.
Also I would recommend checking on the trophy/achievement forums on the web for help on how to unlock it. ^DB