I have no specific knowledge of the details of this flight.

Going only by the description, I wonder if it was a failed/stuck check valve in the fuel venting system. The fuel venting system allows air to enter the fuel tanks to replace the fuel that is being pumped to the engines. Check valves prevent fuel from flowing into the vent lines as the aircraft maneuvers. If a check valve sticks, it could allow fuel to enter and that fuel to exit the aircraft through the air intake vents.

This is not generally a serious risk to the airplane as jet fuel is not very volatile, unlike gasoline, and is difficult to ignite (unless it is happening in an action movie)

again, just a guess.