Cracked block cause?

You didn't specify 5.9 LA or Magnum. When I was a trainer in the Chrysler training group we would stress this could happen to Magnum engines if the vertical intake bolts were tightened excessively. The Magnum engine intakes only required 12 ft/lbs of torque. I personally only heard one technician verify this actually did happen. Chrysler must have researched warranty cases and put this out to technical training, otherwise we wouldn't have been preaching 12 ft/lbs on the vertical intake bolts