As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXPERIENCED CABIN DEPRESSURIZATION AT ALTITUDE AND THEN DIVERTED. MAINTENANCE FOUND CARGO DOOR RUBBER TRIM SEAL DEBONDED AND HANGING OUT IN THE AIRSTREAM. REINSTALLED CARGO DOOR RUBBER TRIM SEAL IAW AMM 52-30-02. PERFORMED LEAK CHECK ON PRESSURIZATION AND OPS CHECK ON THE PRESSURIZATION SYS IN AUTO AND MANUAL MODE IAW AMM 21-31-00, OPS AND LEAK CHECK GOOD. THE ACFT WAS APPROVED FOR RETURN TO SERVICE.