As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING FLIGHT, NR 1 ENGINE FILTER CLOG LIGHT + ECAM WARNING. THE CREW C/O THE QRH PROCEDURE & STATUS OF WARNING DID NOT CHANGE. NR 1 ENG. IN-FLIGHT S/DOWN WAS C/O THE ACFT RETURNED TO YUL FOR FURTHER INVESTIGATION. FOUND ENGINE FILTER CONTAMINATED WITH METAL. ENGINE REPLACED AND ROUTED TO SHOP FOR INVESTIGATION.