As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING INSPECTION, MAINTENANCE NOTICED THE FUEL TANK FILLER NECK SEEMED TO FLEX MORE THAN NORMAL. AFTER TANK REMOVAL THE FILLER NECK WAS FOUND TO BE SEALED TO THE TANK WITH AN UNSPECIFIED SEALING COMPOUND. THE SEALER WAS REMOVED, REVEALING THE NECK TO BE CRACKED AROUND ITS ENTIRE CIRCUMFERENCE.