I had a new CX-3 last December which for many reasons was graciously replaced with a new CX-5 this past March. Mazda was very understanding and cordial about the whole thing.
But there are still many little irritations about these vehicles. For instance, the Bluetooth range is a joke: if you are more than 4 feet from the vehicle, the system does not see your phone and will not connect. I had the car running last week, went to get something in my house, came back, got in, and the stupid BT wouldn't connect my phone. My Cadillac has a BT range of 50 feet!
Yes, I've had the "I think I'll lock your doors now, but then again, maybe I won't" issue since getting this CX-5. Sometimes it's based on where you are. If I go to my Starbuck's, for some reason, it won't lock. Of course the system is set up so that if you get out and walk around back, that rear sensor knows you're still near the car and won't finish the locking process. But if you get out and go around the front of the vehicle, it will finish the locking process.
It's quite annoying since you're "trained" by the idiosyncrasies of the vehicle to listen for that second beep to ensure the doors locked. If Mazda is going to offer a way to auto-lock, it should work consistently.
UPDATE...just went out to unsuccessfully update Gracenote (guess the dealer has to do it). Got in the passenger side and when I got out and walked away, no locking sequence. Doors remained unlocked until I use the fob. Dumb ass car.