As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LGA - CLIMBING THROUGH 10000 FEET NOTICED UNWANTED FUEL TRANSFER FROM CENTER TANK TO LEFT WING TANK. RETURNED TO LGA AND LANDED WITHOUT INCIDENT. FOUND PIPE CRACKED IN LEFT HAND WING TANK. REPLACED LEFT WING MAIN TANK FUEL SYSTEM PIPE ASSEMBLY. SYSTEM GROUND CHECKED NORMAL OPERATION.