A rattle by itself doesn’t prove the lens is faulty. The useful question is whether the lens is operating within spec. If autofocus, aperture control, zoom/focus action, and image quality all work normally, the sound may be harmless. Since anecdotal reports like “mine does that too” aren’t very meaningful, the best approach is to test the lens systematically: check sharpness at different focal lengths and apertures, confirm autofocus accuracy and consistency, inspect for unusual play in the barrel, and make sure the aperture responds correctly. If it passes those checks and produces normal images, there’s less reason to worry. If you notice inconsistent focus, poor sharpness, mechanical looseness, or other abnormal behavior, then the rattle may indicate a problem worth having inspected.