Entities take fall damage on moving slime blocks

If a Slime block is moved when a mob lands on it the mob takes fall damage. For a demonstration see the attached video.

Steps to reproduce:

1. Build the setup shown in the attached image . [between the slime block and the fence gate are four air blocks (five also works)]

   

2. Place yourself or a mob on top the fence gate [the example mob shown in the demonstration is a villager spawned via a command block five blocks above the fence gate that spawns a "/summon minecart ~ ~-3 ~ {Passengers:[{id:"minecraft:pig"}]}"]

3. then trigger it with an observer

4. Observe the entity clearly taking damage

Currently the exact cause of this behaviour is unknown so there are likely many more configurations that result in the mob taking damage.

An additional note: It seems that very small mobs like armadillos and cats are not affected by this but pigs and larger seem to be affected eg. Villager, cow, llama etc