Last modified: 2014-10-02 07:59:59 UTC
I checked the last round of translation notifications and out of few hundreds edits there were 4 which were not top revision: https://meta.wikimedia.org/w/index.php?title=User_talk%3AFerdous&diff=9604870&oldid=9604186 https://meta.wikimedia.org/w/index.php?title=User_talk%3AAnn_jordan999&diff=9604872&oldid=9604190 https://meta.wikimedia.org/w/index.php?title=User%20talk:Johalmohammad&action=history https://meta.wikimedia.org/w/index.php?title=User%20talk:M.s.fernando&action=history They appear to be specific users who for some reason keep receiving two copies of each notification. Maybe someone can check if there's something special about them in the jobqueue logs or in the DB?
Note that in some of those there are slight differences between the two copies.