Carpet Bug

What I expected to happen was...:
The Bookshelfs increase the xp usage in the Enchantment Table with Carpet
in the floor.

What actually happened was...:
The Carpets blocked the path for the Bockshelf's to take effect in the
enchantment table.

Steps to Reproduce:
1. Place a Enchantment Table
2. Put Bookshelf's around the enchantment table
3. Put Carpets around the enchantment Table