As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FUEL LEAKING INTO CENTER TANK DURING FLIGHT. PUMPED CENTER TANK TO MAKE IT ZERO MULTIPLE TIMES AND FUEL STILL RETURNED. NO FUEL LEAK OR UNWATED TRANSFER TO CENTER TANKS, UNABLE TO DUPLICATE. NO FAULT FOUND. PER FIM TASK 28-21-00-810-812.