I also noticed this occurs; it happens with me too, every time. Same goes for sprint-jumping. My guess is that Minecraft calculates that the player jumps before it calculates the slime block, so the slime block doesn't happen if the player is moving upwards, that's clearly wrong.
I also noticed this occurs; it happens with me too, every time. Same goes for sprint-jumping. My guess is that Minecraft calculates that the player jumps before it calculates the slime block, so the slime block doesn't happen if the player is moving upwards, that's clearly wrong.