Moving from a slime block to honey block with step with reverse mode enabled sends you flying in the air.

[Nixion23]

Moving from a slime block to honey block with step with reverse mode enabled sends you flying in the air fast.

[icaema]

I can reproduce this and it also works with a slime block and any non-full size block.
Stepping from the non full size block to the slime block launches the player.