The piston turned into a headless piston when I tried to push two or more fireballs with a slime block.

When I summoned 2 fireballs(entity id: minecraft:fireball) using command block, (/summon minecraft:fireball ~ ~2 ~) and try to push it with a piston with slime block, it becomes a headless piston. When I put blocks near to it, it doesn't change into a normal piston, and you can use it to break down the bedrock.