As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINEERING REQUESTS APU REPLACEMENT DUE TO FINDINGS FROM LAST LUBE MODULE REPLACEMENT. DEBRIS PREVIOUSLY FOUND IN LUBE MODULE, DETERMINED TO BE M50 MATERIAL. NOT ASSOCIATED WITH LUBE MODULE. ACFT GROUNDED. REPLACED APU IAW TASK CARD 78349010, APU REMOVAL/INSTALLATION.