If a snow layer block is 7 layers tall, it is possible to place a new snow layer block above it without fully completing the block below it, making a 1/8 block wide gap. This only works by stacking snow layers up to 7 layers tall and then placing a snow layer on the side of the block above it. Breaking the snow layer block will destroy all snow layers above it, as intended. This isn't just a graphical glitch, as arrows can be shot through the gaps
Can confirm.