It is possible that with the huge number of people that have been logging in recently that your character is still in queue to be updated - achievements are retrieved through different means than your stats. Logging in and out is generally the method used to make sure they are in the queue, but we don't actually have a mechanism to force updates for individual characters. There have been a lot of characters coming through recently so I can really only say to give it just a bit more time to work through the queue. I know that isn't very helpful