if support is removed from under a gravity affected block by a piston and redstone line adjacent to the block gets depowered, it will pop off as an item instead of falling down.
Note: this issue does not affect dragon eggs, which fall normally.
How to reproduce
[media]Build the contraptions shown in the attached screenshot
flip the levers
For two contraptions on the left flipping the lever causes the gravity affected block to fall normally.
Two on the right make the block pop off as an item.
Please provide the same screenshot of the setup with your F3 debug screen enabled.