The bug

MC-2474 was fixed in 23w14a. However, for flowers, it was only fixed for the two-block-tall kind. One-block-tall flowers still count as obstructions, which is inconsistent.

How to reproduce

1. Create a fully powered up enchanting setup
2. Check that it works
3. Place one block tall flowers between the table and the bookshelves
4. Check again

Expected results

These tiny flowers would not block line of sight to the bookshelf.

Actual results

They do.

How to fix

One-block tall flowers could be made replaceable like other non-obstructing small plants are (fixing MC-118501 as a result), which would mean they wouldn't block bookshelves from interacting with enchanting tables. See also MC-255846.