Glitch in Pokemon Soulsilver?

So I'm doing a run through the elite four for the millionth time. I get to bruno, and naturally I take my Pidgeot out. I take his hitmontop out, no problem, and then he sends his machamp out. Knowing that it knows stone edge, I use fly so I can dodge it. Pidgeot in midair, it gets nailed with stone edge. Right before it comes down, the machoke uses bullet punch, and it HITS. My pidgeot dies, and I have to use another pokemon. What I'm wondering is how Stone Edge and Bullet Punch hit. As far as I know, neither attack can hit airborne pokemon, so I'm wondering whether it's some weird item the Machamp is holding, or if it's just my copy of the game.