Ok, max I just learned how to do this. After learning it, I'm not entirely sure its yawing based since I think I was able to do the same thing at a distance. Whether it speeds up as you get closer needs to be tested a bit more, but I think it was the same speed at a distance. It seems both jack and sushi have know about this for a while now.
Anyways, What I think it is is a combination thats based on how the swing to swing transitions work. Since it chooses an new direction with continual attack, it the transitions go fast in certain combos. That side one you mentioned is a particularly interesting example since the transitions choose those directions after a certain button combination.
On the up side, it can be stopped with a simple parry thanks to the last changes in the parry code. The downside is, if you dont see it coming and don't parry it, it can do alot of damage and so can other combinations that appearently exist. Its kind of like the comboing in the old Killer Instinct game.
Juyo's combination on the side are definitely ALOT faster though because of the way its animation works and it needs to be fixed (ticketed already).
HOWEVER, I asked razor about the seeming speed up on these combinations and he said its not intentional and maybe a bug. He needs to see it in action to be certain though and whether or not he even WANTS it to be fixed since it is a pretty interesting side effect that may or may not be overpowered once its understood.
Btw, Jack. I also talk to razor about the default saberlockfactor and he said to bug ticket it since we all agreed it was a bad thing.
We might also want to make a video of this transition thing since razor doesnt have much time at the moment.