In the 14w04a snapshot when eight rotation possibilities were brought in for item frames. The eight rotation values have also been applied to maps in item frames which means that the values 4, 5, 6, 7 duplicate the original 0, 1, 2 and 3. It is only a minor problem but if someone is using testfor to test for a specific rotation then they would have to test for both 0 and 4 for un-rotated and so on