Season 1 of Star Wars rebels is (it appears) missing episode #12 entirely, but in reality it is missing episode 4 "Fighter Flight". This episode, when inserted at #4 will push the other up the list and take up the slot for #12.
Yea, thanks @Adrian. The bottom line is there is a missing episode. It is blatantly obvious but IMDB doesn't seem to care. I guess we'll just live with incomplete data with this show. I'm sorta tired of trying.