2015 Forester won't lock, thinks a door is open

Hi,

This started a couple days ago. I hit the LOCK button on my key fob and the lights blinked twice instead of once. This usually means a door isn't quite closed. I opened all of them and closed them firmly and it locked. This evening when we got home, the same thing happened only no matter how hard we slammed everything shut, I still got the double blink. We ended up locking it with the interior door lock button on the driver door and then using the key to manually lock the driver door. I was worried that the lights might stay on since it was acting like a door was open, but they shut off like they were closed. We have had problems in the past with the back hatch not reading as completely closed, but a firm closing has always taken care of it. Nothing is obstructing any of the doors or the hatch that I can see. Any suggestions before I take it in to the dealer?

Thanks!