As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: #2 PACK SURGING CAUSING PRESSURIZATION TO SWING, V/S +250 - 450FPM AT FL340. **SUPPLEMENTAL REPORT FOR AALA202107149594: REPLACED #2 ENGINE PRESSURE REGULATOR VALVE AND ACCOMPLISHED A SATISFACTORY LEAK / OPERATIONAL CHECK PER AMM 36-11-52 AND 21-51-00. ** (CLSOED)