As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE OPERATING ALL OUT OF NR 2 FUEL TANK, THE NR 3 TANK DECREASED SLOWLY IN QUANTITY WITH ONLY THE AFT PUMP OPERATING. LEAKED 1,200 LBS OVER 1 HOUR 15 MINUTES. TURNING OFF BOTH BOOST PUMPS QUANTITY DECREASE STOPPED. FOUND BROKEN VENT TUBE AND REPLACED TUBE.