That IS weird! First I would turn off auto start since you are plugged in. Next, at some point I would unplug, turn auto start on and see what happens. Sensor for low battery may be bad causing auto start even when batteries are charged. Or maybe you have one of those little electrical gremlins that are hard to find and very annoying! Not a big fan of auto start, have seen to many problems with it.
Dave & Myra
One day your life will flash before your eyes,
make sure it's worth watching!