My 2017 RX 350 would beep 10 times when I unlocked the drivers side door. A while back I discovered the lock actuator on my passenger side rear door would stick about halfway down. So when I would leave my car and lock it with the fob or by touching the outside handle lock indent, the car seemed to lock fine. All four doors and tailgate did lock. Somehow, whenever the lock actuator didn’t engage and sink down fully (even though the door DID lock, the car detected it and would beep 10 times when I unlocked the door using the drivers side handle. It didn’t beep using the remote, BTW.
To fix it, go to the affending actuator and open the door, then push down the lock and then close the door. It usually then works until someone opens the door manually, then it starts again.
