Snow 2-8 layers doesn't block the bookshelves

Summary:
Snow is only replaceable when it has 1 layer. Accordingly, when the snow layer has 2-8 layers, it must block the bookshelves. But bookshelves are not blocked by snow when they have 2 or more layers.

Steps to reproduce:

1. Place Enchanting Tables and Bookshelves.
2. Between them place snow layers with 2-8 layers.

Observed results:
Snow Layers (2-8 layers) are non-replaceable blocks and do not block Bookshelves.

Expected results:
As Snow Layers (2-8 layers) are non-replaceable blocks, they should get in the way of the Enchanting Table.

Screenshots: