I saw a couple of people post that they had problems, but everything's still been working fine for me; unlocked one on Wednesday and 2 yesterday without any issues. I wonder if it matters what region you're in or something? I might hold off on any more for a bit just to be safe, since they never did fix the achievements that didn't sync last time for people.
Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete.
Otherwise, please post a new thread in this forum instead.