As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. CABIN PRESSURIZATION FLUCTUATING AT 350. THE CABIN CLIMBED TO 8800 FEET THEN DESCENDED NORMALLY. CABIN PRESSURE WAS USING SYSTEM 2. NO ECAM WARNING. REMOVED AND REPLACED CABIN PRESSURE CONTROLLER 2 AND PERFORMED SATISFACTORY OPERATIONAL TEST, IAW AMM 21-31-34.