As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SUPPLEMENTAL LOST PRESSURIZATION AT APPROX 13,500 COULD CABIN ALT (2000) FEET WAS THE BEST. DEFER AUTO PRES M PROCEDURES C/W MANUAL PRESS OPS CHECK GOOD IAW AMM 21-31-00 MEL 21-17 AUTH 060107DM-C MOC 607038. REMOVED AND REPLACED FLAPPER VALVE IAW AMM 21-22-04. OPS CHECK GOOD. REFER AML 4538336/1. MEL RESTORED "M" PROCEDURES REVERSED.