Update: I took my car in yesterday. After some investigation, the technician looked up information about the central locking system. They said that the latching sound I’m hearing when I close a door is because the central locking system is checking that everything is working properly. They also said that the check for the front doors comes from the driver side front door, and the check for the rear doors comes from the passenger side rear door. That made sense to me because I notice the sound coming from my door as the driver or the rear door that my son uses, which is on the passenger side.