The bug

When standing on snow layers, the Y position of the player should always be 0.125 blocks lower (or one layer less) than the visual size.

However, if you stack 9 layers of snow (1 full block and 1 layer), the player sinks 0.250 blocks lower (2 layers). That means that both 8 layers and 9 layers have a height of 0.875 blocks and 10 layers have a height of 1.125 blocks.

I believe that the player should not be able to sink lower than just one layer of snow, and the height of 9 layers should be the same as a snow block and 1 layer of snow – 1 full block.