Hello - in less than a month, my G37's left rear door sealer rubber is falling off. It became very loose and not securely attached to the door compared to the right rear door's sealer rubber. I'm trying to fix it myself but not sure how the rubber is attached to the door frame. I saw a little plastic hook attached to the rubber, does anyone know how this hook is attached to the door?

 

I'd take it to the dealership, especially since the car is brand new. They should be able to address if you need something more involved than just re-seating the seal.