Closing and reopening world while in sand causes floating sand

I was playing around in creative mode and found this glitch.

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What I expected to happen was:
After trapping myself in sand, quitting to title, and going back in the world, I would stay in the sand.
What actually happened was:
I was in a hole in the tower with sand floating above me.
Steps to Reproduce:
1. Build a 1x1 tower of sand up to build limit.
2. Break the bottom sand and immediately walk into the tower.
3. Pause, save and quit to title, and go back in the world.