Steps to reproduce:

1. place down a grass block and then place tall grass above it
2. build up 3 blocks next to the tall grass so there is a block to the side and 1 block up from the top of the tall grass
3. place sand next to the block, so that it rests on top of the tall grass
4. break the tall grass from the bottom half
5. the sand will float in the air until it receives a block update
   Expected behavior:
   The sand block should fall when the tall grass is broken, regardless of whether the top or bottom half was targeted.
   It should also be noted that this works with all double tall flowers and the double tall fern as well as tall grass.