I've owned by 2015 Lacrosse for a year now. During this time, approximately 50% of the time when I shut off the ignition, the car horn will chirp 3 times, and then the doors will automatically unlock. I always put the car in park, then push the ignition button off before doing anything else. I don't attempt to move the keyfob, nor do I begin to open the car door. Simply shutting the car off and not moving a muscle is all it takes for the car to honk 3x. It's embarrassing when I park in the garage at work and then my car begins honking for no reason. I can't seem to find anything online about this, and would appreciate some guidance.

Thanks.