I did put some foam under that corner but gained no effect (dealer coudn't duplicate it). I removed the the whole panel and put foam under all 4 corners plus some more along the sides and it was gone for about a week. But it came back but less. Now it happened (when temp is low) only during the first couple miles. I don't understand how it'd rattle in a couple of minutes and then gone completely until the next drive

. Now I am not even sure if the rattle came from there, I'll wait until there is a tsb available and bring it back to the dealer.