As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLE FLIGHT NR 3219 THE CREW REPORTED DURING CLIMBOUT THE AIRCRAFT PRESSURIZATION SURGED, CABIN RATE WENT FROM 1750 TO 1800. RESET TO MANUAL AND LOST CABIN ALTITUDE INDICATION. THE AIRCRAFT RETURNED TO CLEVELAND AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND THE PNEUMATIC OUTFLOW VALVE WAS LEAKING. THE OUTFLOW VALVE WAS REPLACED AND OPERATIONAL CHECKS WERE GOOD.