As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DEPARTURE CLIMB, THE EXHAUST RISER ON THE LEFT ENGINE NR 2 CYLINDER DEVELOPED A HOLE ON THE LOWER SIDE. PRIOR TO THE FAILURE OF THE PART IT APPEARED TO BE IN GOOD CONDITION. DURING THE PRECEDING FEW HOURS OF FLIGHT THE AIRCRAFT WAS USED FOR FLIGHT TRAINING INCLUDING SINGLE ENGINE PROCEDURES AT WHICH TIME IT IS POSSIBLE THAT SHOCK COOLING MAY HAVE BEEN INDUCED THAT COULD HAVE STARTED THE CRACK WHICH LED TO THE FAILURE OF THE PART.