As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER DEPARTURE, THE CREW OBSERVED A PRESSURE LOCK NOT ENGAGED INDICATION FOR THE MAIN PAX DOOR. THE ACFT RETURNED TO POINT OF DEPARTURE AND LANDED WITHOUT INCIDENT. MX FOUND ICE IN THE DESICCANT CARTRIDGE. THE ICE WAS REMOVED AND HEAT APPLIED AFTER WHICH THE SYSTEM WAS CHECKED SERVICEABLE AND THE ACFT RETURNED TO SERVICE.