Similar issue as Java's MC-2474, which was fixed in 1.20 snapshot, but not on Bedrock.

Replaceable blocks placed between bookshelves and enchanting tables negate bonuses received from bookshelves. The following blocks that blocks/negate bonuses from bookshelves are as follows:

Lava, Grass, Fern, Dead Bush, Seagrass, Tall Seagrass, Fire, Soul Fire, Vine, Glow Lichen, Tall Grass, Large Fern, Bubble Column, Warped Roots, Nether Sprouts, Crimson Roots, And Hanging Roots.

Steps to Reproduce

1. Build the setup shown in the attachment below.
   
2. Obtain some lapis along with any enchantable tools/weapons.
3. Place it inside the enchanting table and take note of the enchantments available.
4. Place some replaceable blocks in between the bookshelves and the enchanting tables.
5. Place the enchantable tools/weapons inside the enchanting table.
6. Take note as to whether or not replaceable blocks placed between bookshelves and enchanting tables negate bonuses received from bookshelves.

Observed Result
Replaceable blocks negate bonuses received from bookshelves.

Expected Result
Replaceable blocks would not negate bonuses received from bookshelves.