As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNWANTED FUEL TRANSFER FROM CTR INTO NR 2 MAIN TANK IN FIRST HOUR OF FLIGHT. TANK ENTRY & TROUBLESHOOTING IDENTIFIED FUEL JETTISON PUMP CHECK VALVE NOT FULLY CLOSING. REPLACED VALVE & AIRCRAFT RETURNED TO SERVICE. SUSPECT VALVE WEAR LED TO HANG-UP WHICH PREVENTED CLOSING.