As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOSS OF CABIN PRESSURIZATION OCCURRED AT 33,000 FEET UPON SELECTION OF ENGINE AND AIRFOIL ANTI-ICE. CABIN ALTITUDE REACHED 10,000 FEET AND EMERGENCY DESCENT WAS MADE TO 18,000 FEET. CABIN PRESSURE WAS REGAINED AND FLIGHT CONTINUED TO MEM WITHOUT FURTHER INCIDENT. REPLACED CABIN PRESSURE CONTROLLER AND RETORQUED CLAMP ON CROSSOVER DUCTS. OPERATIONAL CHECK NORMAL AND AIRCRAFT RETURNED TO SERVICE.