As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MC REPORTS CREW REPORTED LEFT DUCT PRESSURE READING HIGHER THAN EXPECTED DURING TAKEOFF. CRUISE PRESSURE NORMAL PRI: 1ETOPS SIGNIFICANT SYSTEM. GROUNDED - YES. REMOVED AND REPLACED NR 1 HIGH STAGE VALVE REF AMM 36-11-06 AND NR 1 HIGH STAGE REGULATOR REF AMM 36-11-07. LEAK CHECK GOOD. NO HISTORY 90 DAYS OF DUCT SPLIT OR ABNORMAL PRESSURES ON NR 1 OR NR 2 ENGINES. NO TROUBLESHOOTING COMPLETED. REPLACED PARTS AS DIRECTED BY TECH SERVICES.