As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAV DOOR CAME OFF INFLIGHT. BOTH PILOTS CHECKED THAT IT WAS SECURELY CLOSED WITH ALL 3 LATCHES CLOSED AND KEY LOCKED PRIOR TO ENGINE START. CES SCREEN ALSO SHOWED ALL ACCESS DOORS CLOSED PRIOR TO FLIGHT. REMOVED & REPLACED SERVICE DOOR IAW CL-650 SRM 51-54-04.