As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING C-10 CHECK, INTERGRANULAR CORROSION WAS FOUND ON AFT SIDE OF AFT THRESHOLD DRAIN OF R-1 DOOR THRESHOLD (INTERCOSTAL) AT NUT PLATE HOLES BS 370, WL 208.1. MAINTENANCE REMOVED CORRODED INTERCOSTAL AT BS 337, WL 208.1; FABRICATED AND INSTALLED A NEW REPLACEMENT INTERCOSTAL PER DWG 141N5160.