I find it difficult to believe that engines with a history, down thru the years, of outstanding reliability (as is the case with our Duramax's of various series) absent abuse, meaning trying to draw significantly more power out of them then the stock "rating", will incur this kind of failure.
I have worked on and around all manner of internal combustion engines (probably a bit more than any of you in here). I have yet to see an engine do what this one did absent major abuse.
Bottom line - those of you with stock engines, and those of us who have a "tune" to take advantage of our "deletes" (but are conservative in the use of the additional power) do not have anything to worry about.
If you read enough on this forum you will see that this is in fact quite true. The duramax engine has a long history of breaking cranks at that location. This is so much of a common issue that people have created cam shafts with altered firing orders to try to remove the stress from that point on the crank. Plenty of stock trucks have broken cranks like this. There is also a track record of sheering the key out of the crank and cam as well which results in valve and piston collisions.
The Duramax engine is an exceptional engine, but it is also far from perfect. There are plenty of issues with it from the beginning of the series, most have been corrected by this point but the crank issue as far as i am aware has never been addressed by GM. It is not a huge issue, as failures are rare, but there is still a clear history of failures going back to the 01 trucks. The issues with head gaskets, injectors, cp4, are all significantly more common issues though, so that is mostly what you see / hear about.
There are also people making well over 1K HP on a stock crank with no failures, and others who break them on stock trucks. There seems to be little rhyme or reason as to why. Perhaps its a heat treating issue, maybe there's multiple production locations and one is slight harder, who knows, but this does happen.