Gravity affected blocks break when piston/sticky piston retracts

Summary:
When a sticky piston pushes a gravity affected block upwards then downwards, the block itself is destroyed.

Steps to Reproduce:

1. Place a sticky piston facing upwards
2. Place two or more gravity affected blocks (sand, gravel, concrete powder, anvils) on top of the sticky piston
3. Extend and retract the sticky piston

Observed Results:
The block breaks when the sticky piston retracts.

Expected Results:
The block should not break when the sticky piston retracts.