4 way flasher came on by themselves after starting vehicle

Yesterday, I started by 2014 Prius v and immediately pushed the EV button, as I was only backing my car out of the driveway and parking in the street. I noticed that my 4 way flashers came on for a couple of blinks and then stopped blinking. When I parked the car and attempted to lock it using the driver's door handle, it gave a long, continuous sound, like the door was not closed, but it was. I opened the door and then closed it again, and tried again to lock the car. This time, it worked. I brought it to the dealer today for normal 45,000 mile service, and mentioned these peculiar happenings. They ran some test, but found nothing wrong. Does anyone have any ideas? Or has this happened to anyone else?

 

On my service slip, they wrote down next to battery state of health "310 pass"