Causes of castbirin durch ovens to crack.

[Woodbutcher-TNT]

I cook my corn bread in a cast iron skillet in the house. Never tried it in a DO. But I always preheat my skillet before pouring in the batter. Never had a problem.

 

[S. Heisley]

Drastic changes of temperatures can cause cast iron to crack; but, maybe there was a small, nearly invisible fissure or a weak spot already in the DO. You may never know the full answer.