In other words; sand does not fall after removing 2-block tall flowers below them

What I expected to happen was...:
Sand would fall as usual

What actually happened was...:
Sand did not fall

Steps to Reproduce:
1. Take some sand, 2-block tall flowers and preferably grass blocks with you.
2. Place the grass blocks, then place the 2-block tall flowers above them and then place sand above them.
3. Remove either the 2-block tall flowers or the grass blocks.
4. You'll see sand is not falling. This doesn't work for 1-block tall flowers.

See this video for more info:
https://www.youtube.com/watch?v=fF8By1S0Hrc

(if this issue gets resolved as dupe or WAI I will go flip)