As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 668 MCO-BUF, AIR RETURN TO MCO - CREW DECLARED EMERGENCY DUE TO AMS CTRL FAIL AT FL350. BEGAN LOSING PRESSURIZATION ABOUT 2500 FEET PER MINUTE. PER QRH DESCENDED TO 10000FT. ALSO ANTI ICE WHITE CAS CAME ON SIMULTANEOUSLY. REMOVED AND REPLACED AMS CTRL NR 2 AND FAULT CLEARED REFERENCE AMM 21-00-01. ALL OPS CHECK GOOD.