The pass. seat on my '07 does this, mirror is OK tho.
Try adjusting the seatback angle, I noticed some settings seemed more prone to making it do this than others. For mine, the more upright it is, the less it shakes.
Try adjusting the seatback angle, I noticed some settings seemed more prone to making it do this than others. For mine, the more upright it is, the less it shakes.