Ive got a rattle in my 2018 ... don't think it is seatbelts as I latched them all and rattle continues. Might be the rear seat? I noticed that when I fold up the rear seat it locks in the up position so I need to pull the latch to lower the seat but it doesn't seem to lock when it the down (regular) postion. Anyone know it the seat is supposed to lock when down and if it is, how to make it lock?