Hi Askers,
I've had my GT Line RWD for a similar amount of time and also love the car.
I did read somewhere that a bad batch of 12v batteries were shipped out with very first batch of EV6's.
If it's any help I have had no 12v battery issues at all, we have had some really cold and frosty nights here.
So hopefully it was just a one off.
Regards, Del.