I'm having the same problem.
Hired a driver to take me to Newark airport and then drive the car back home. That was close to 5 hours of driving. So the battery had a good charge.
Came home after 10 days. The car was parked in the garage, so no cold weather and went I started it I got the warning about incresed battery dischaged while parked. I started it and cleared the control message. When I turned the car off, the display said charge battery. So, I hooked up the battery tender and left it on for 3 days. No change. I went down to the garage and started it and the display is still telling me I have a low battery. Appointment made at the dealer. I typically don't drive this car most of the summer, so it's nothing for this car to have sat 6 weeks at a time and not been started and I've never had this message. I'd say it's time for a new battery.