when sleeping in a bed i slide off

when i sleep in a bed that has a block 2 spaces above the head of the bed it causes my character's visual to slide off the bed. this only occurs with whole blocks above the bed. does not work for fences, slabs, stairs or other partial blocks. also, this bug is best viewed with the bed facing east to west because i only slide off to the south. if the bed is facing north to south, the visual slides backwards or forwards off the bed( to the south)