Looks to me like you are playing with the twin engine fighter optional rule, which reduces the combat results of twin engine fighters by one (AX -> DX, DX -> AA, AA -> DA, DA -> NE, NE -> AC, AC -> DC) when fighting against single engine fighters. If you are playing with that rule (which is one of the better optional rules in the game, IMHO), no bug.
I assume that the Allies had a lot of surprise points, otherwise the air-to-air values don't make sense.