2021 Highlander Hybrid Limited AWD here, and I have noticed that when I start the car, the dash warns me about the rear seat belts needing to be buckled but there is nobody sitting there (and nothing in the seats at all - both 2d and third rows empty, third row is usually folded down). Is this normal? Is this a defect? Its only mildly annoying but if it is a glitch there could be other symptoms I haven't figured out yet.