Straw Bed - Shadow across centre when viewing from side at distance

Place down a Straw Bed (place multiple straw beds side by side to more easily view the problem), stand to one side of the bed, whilst looking at the bed walk directly backwards, once you have walked 9 (or more) blocks (from the furthest straw bed) you will see a black line / shadow fade in to view. It will be pointing towards you and will be going through the centre of the straw bed. I expect that this should not appear.