It is because of this :
Thanks to everyone who participated! If you voted in this event, you received 1 merit; if your caption appeared in the first table above, you also received 10, and if your caption appeared only in the second table above, you also received 2.
You can lock the thread, there are already many with same question. One should atleast check the recent threads if anyone else has a same problem, it would avoid this multiple threads on same issue.