Presumably caused by MC-261616.

The bug

A minecraft:sculk_veins between an enchanting table and a bookshelf will stop the enchanting table from benefitting from that bookshelf.

This directly contradicts what is stated in the 23w14a patch notes (https://www.minecraft.net/en-us/article/minecraft-snapshot-23w14a):
Replaceable blocks no longer block the connection between Enchanting Tables and Bookshelves

How to reproduce

1. Create a fully powered enchanting setup
2. Check that it works
3. Fill in the gaps between the bookshelf and table with sculk veins
4. Check a second time

Expected results

As sculk veins are replaceable blocks, they should not get in the way of the enchating table.

Actual results

They do.

How to fix

Add minecraft:sculk_veins to the block tag #minecraft:replaceable.