As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FUEL VENT FLOAT VALVE IN THE TOP OF THE RT NACELLE TANK WAS IMPROPERLY INSTALLED. THE FLOAT PIVOT BRACKET WAS BENT. THIS WOULD PREVENT THE VALVE FROM SEATING PROPERLY. THIS WAS ALLOWING FUEL TO TRANSFER INTO THE AUX TANK WHEN EVER THE MAIN TANK WAS FULL.