As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING THE OVERHAUL OF THIS ENGINE NEW ROLLERS (PN 5999) WERE INSTALLED. DURING THE TEST RUN OF THE SUBJECT ENGINE ONE OF THE ROLLERS FAILED. AFTER TEAR DOWN, A HARDNESS TEST INSPECTION OF THE ROLLERS WAS CONDUCTED AND IT WAS DETERMINED THE ROLLER THAT FAILED, WAS CONSIDERABLY SOFTER THAN THE REMAINING ROLLERS. (SW15200313699)