As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 ENGINE HPT DAMAGE. REPLACED NR 1 ENGINE. SHOP TEARDOWN FOUND A MISSING HP TURBINE STAGE-2 DUCT SEGMENT. ADJACENT SEGMENTS HAD FOREIGN MATERIAL LODGED IN THE INTERNAL COOLING PASSAGES THAT CHOKED OFF COOLING AIR. THIS CAUSED BOWING, WHICH LEAD TO HEAVY BLADE RUB AND EVENTUAL SEGMENT LIBERATION.