Mine is reasonably tight. There is a very tiny bit of movement with the door shut. The gap is no more than a hair wide. It does not really feel 'loose and rattly', but if I try to wiggle it with my finger or tap on it, I can hear the door rattle, telling me it is not 100% solid to the camera. It is not overly noticeable.
With the door open, you should see the tiny spring and just above the spring is a flat clip. Maybe the little screw on that clip is loose. That clip slides along the hinge pin and keeps the door in its lock position.