So somehow I beat the Edge in 2 seconds. I don't know what weight there is to me saying this, but I did not use any hacks. From what I can tell, my controller stopped working, and I got hit by his 3 hit combo in the first phase, and then the fight just ended. I'm not submitting this as a WR or anything, I just thought it could be useful someone else trying for it.
Yeah, this is something that's well known. I believe it happens if you restart the fight right after defeating him in phase 4 (I forget the exact timing). Then you restart but his health hasn't correctly reset so that happens.