As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) CABIN PRESSURE STARTED TO CLIMB AFTER PASSING THROUGH 18,000 FEET. MAINTENANCE TROUBLESHOOTING REVEALED SWITCH ON APU BLEED VALVE (199H) FAILED IN THE OPEN POSITION. TEAR DOWN REPORT REQUESTED FROM FALCON JET FOR DEFECTIVE VALVE.