As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE DOING ROUTINE MAINTENANCE, WE RETRACTED THE FLAPS AND HEARD A CHATTERING SOUND AT THE TOP OF THE TRAVEL. THE FLAPS WERE DEPLOYED AND WE NOTICED A CRACK ON THE RT OTBD FLAP ACTUATOR PISTON. THE CRACK STARTED AT THE LOWER ROLL PIN HOLE AND WENT UP 4".