I thought the story with Fallen was that Duffel was all set to get on, but while he was out filming with the Chief, he got a clip, some sort of a high risk gnarly maneuver since it's Duffel you know. He was psyched he got the trick, but Chief told him he needed to do the trick again to get a second angle. Duffel was not down with risking it just to do the trick a second time, so they got into an argument that ended with him quitting Fallen, throwing off his kicks, and walking home from the spot shoeless.
I don't remember where I heard this, if it was gossip or from a reliable source. Seems like it was reliable though. I hope it is really what happened, cause it sounds pretty fuckin cool of Duffman.
Oh, and Foundation better not kick him off. That shit would be whack.