As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FLIGHT LEVEL 25,000 FT, IT WAS OBSERVED CABIN PRESSURE WAS CLIMBING 1,000 FT - 2,000 FT PER MINUTE. AIRCRAFT RETURNED TO BASE WITHOUT INCIDENT. CABIN PRESSURE CONTROL PANEL REPLACED AND CHECKED SERVICEABLE IAW WITH MM 21-30-00. NO FURTHER INCIDENT DURING SUBSEQUENT FLIGHT.