I heard it in mine, and realized this is a fuel injected engine. When you turn on the key, it pumps up the system to the required fuel pressure, then when you start it, it doesn't come right back on until the pressure requirement or computer delay time is reached, then mine stays on after that. Is that what you folks hear?
Gas fuel injection is a bit different than the diesel fuel injection I work with every day, but they still have to get the fuel under pressure up to the injector so that it will be able to atomize it when called for. I suspect the pump is near the tank, or even in it like a car's fuel pump, and built into the pickup/float level assembly.
Does make some noise, doesn't it?