Whenever someone sits on the passenger side, I hear a "clunk" sound coming from that seat during driving. (In other words, this is NOT when the person initially sits down, but as the car is moving.)
It does not matter the size of person - from tiny (108#) to 225+, 6'3".

At a recent service, I had dealership check it - they said they could not replicate (probably because they just sat down once - worst Jag dealership ever!).

Anyone else notice anything similar?