Ignition Key Reminder Operation
WARNING: This page is about a different car, the 2008 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
If the electrical key is still inserted in the key slot and driver side door is opened, the door cannot be locked using the door knob, but if operated, automatically unlocks the door again instead. If the door is locked with the manual door lock SW on the driver door or with the door key SW on driver door, the door locks once but immediately after, it unlocks again automatically.