I have the green LED lighted ring on the charging port of my 2018 Volt LT. As I understand it, it is supposed to light up when you open the charge port door, to help you plug in when it is dark. It also flashes like the light on the top of the instrument panel, to indicate the increasing state of charge, but for me that is not the main purpose. At any rate, if I turn off the car, climb out, and fairly promptly grab the cord and open the charge port door, the LED will come on as expected. But if I take my time getting the cord, and don't open the charge port door until after a bit of a delay--no LED light. Is that the nominal behavior? Thanks.