I have been having the same problem for about 4 months now. I called service and they said they were going to run some tests.
They called back and said the battery was fine so everything should be fine.
I have been getting about 2 mi/kWh and a couple of times 1.6 m/kWh. I keep telling them that my driving pattern and habits has not changed at all.
I charged to 395 the night before last. yesterday afternoon I got in the car and it was about 374. Last night it had 354 after 2 miles of driving. This morning it had 294. My mi/kWh is 0.11.
Passive unlock has been turned off, my fob has always been kept in a Faraday box.