This happened to my wife as she was parking in our garage, as soon as it connected to the home wifi it started. She hadn't even parked the car nor plugged in the charging cable as is her habit.
Since owning the car, I have always sat in it during updates. It has become a ritual for me, I know what the car goes through when it updates and pretty much expect to hear and see the same pattern. So, I decided to let it go do it's thing, sat in the car and it didn't have the same pattern I was expecting. It appeared to have went through the update and back to the normal screen when I got the normal notification of a available update on the car. It was the same update, I decided to let it do it again, this time was more what I expected.
Other than that, the car seems to be running normal.