I think there is something loose inside my 15 Pro Max

So, I sometimes use the shake functionality to recover recently deleted emails, and so yesterday, for the first time, I used this feature on my 15 Pro Max. The thing is, while I did it, I heard a sound, like a rattle sound, like something is loose inside. I don't know if this is the cameras, as I know that they move for stabilization or something else, so I decided to ask Apple, to which of my surprises, they did not ask, just insisted to get the iPhone replaced.

The iPhone is working fine, and I see myself lucky because my unit was immaculate, comparing to other people, but now I wonder, is this the camera, is it normal? All my other iPhones did not have this happen. My last previous iPhone was an iPhone 13 Pro Max, and never heard anything.