2022 Outlander locking issue

I don't think this has been brought up. I locked my car via the remote from inside the house. I heard the horn, signaling that the car locked. Got up in the morning and noticed my rear door slightly open. Thought someone broke into it , thankfully I was wrong. My wife claimed she forgot to shut it after taking my granddaughter out.
Why does the horn signal car is locked if a door is open? This is a big flaw in the security of the vehicle. I phisically go out and check the vehicle before locking it now. Never seen this happen in any of my other vehicles, the horn wouldn't beep if a door was not fully shut.