When the player breaks an empty chiseled bookshelf, block updates are not sent to powered comparators 2 blocks that are observing the bookshelf. 

Steps to Reproduce:

1. Place a comparator facing away from a solid block (like stone).
2. Place a chiseled bookshelf beside the stone so that the comparator observes the bookshelf.
3. Place a book in any slot of the bookshelf and then remove the book.
4. Break the chiseled bookshelf.
5. Verify the comparator remains powered.
6. Produce any block update next to the comparator.
7. Verify the comparator is now unpowered.