Pistons with sand are incorrect after reloading the world

Steps to Reproduce:

1. Make the piston with sand in this video.

2. Saving and reloading the world.

Observed results: pistons with sand are incorrect after reloading the world.

Expected results: pistons with sand should be correctly.

Video: https://drive.google.com/file/d/1T1biy5Iv3Xi7HH21OqKJXm7j1LQL9IXf/view?usp=drivesdk