Wow you must have a better eye than me...I dont see any dishing of the sprocket from either of those pics. The pics are better than nothing to get a general idea of where the hub broke, however, there is NO WAY a person could determine if there is a casting flaw in that hub from those blurry pics. Take it to the dealer and tell them the same thing you've said here...the sprocket bolts were tight and the chain was adjusted to specs. Hopefully, they will value your business and be less skeptical than the folks here. If you look at the third photo you can see that the sproket is pulled over or bent. Not really an even pull or dish, but still the same effect. It obviously was pulled out and over. And you're right, the photos can't show any casting flaws. Hope I didn't imply that.