Taking fall damage that shouldn’t occur

When high up in the atmosphere(around y level 256), my game starts to display that I am drowning(note there is water at y level 64 right below my location) and then when I walk over an area of blocks that are further below me, I start to take fall damage. I am unsure if this may be a performance issue in my mobile device or if this is and actual bug but it is greatly affecting my gameplay.