I remember looking on this brilliant forum a while back to try to ascertain the location of a rattle from the rear of my 2022 Kodiaq 7 seater. A few suggestions directed me to the second row seat belt clasp as it goes into the roof socket or the ones on the seat but it was still there.

I finally discovered what it was and thought it might be useful for others.

If you slide the rear seats forward then return them to their correct position, the handle under the front of the seat is the rattle. I found this by lifting it slightly and it seemed to clock into place.

Each time I've had the rattle since, just a quick lift if the handle has cured it.

That's really helpful, nice one AG.