Invincible Sand block

I'll try to make a sand block bounce twice using a piston and a slime block.

Once vertically and once horizontally, to create a sort of “sand block launcher.”

The problem is that when the second piston and slime block hit the sand block to propel it forward, visually the block is propelled forward, but this is only a visual effect—the sand block is still bouncing off the first slime block but is invincible.

When that block stops bouncing, the visual block teleports to the invisible block’s location