Blocks placed on pistons will break when pistons retract

In 1.9, blocks that can only be placed on other blocks (such as redstone dust, and buttons) can now be placed on top of pistons. However, when the piston retracts, the block placed on the piston will break. To reproduce this issue, place a piston facing in any direction besides up, and place a button on top of the piston. The button will break when this piston retracts.