As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU RUNNING AT GATE FOREIGN MATERIAL EXITING APU EXHAUST. PER AMM, CHECK MAG PLUG CHIP DETECTORS. IF OK, CHECK INLET DUCT PATH FOR DAMAGE OR DELAMINATION IF OK REF: AMM AND INSPECT FOR DAMAGE. COMPLETED APU REMOVAL AND INSTALL REF AMM. DAMAGED BLADES FOUND ON BOROSCOPE. COMPLETED APU INSTALLATION. LEAK CHECK GOOD.