While sprinting in survival and quickly placing then destroying the slime block, it will sometimes temporarily spawn a slime ghost block, a block that has no effect but has the texture. As you can see in the screenshots below I was playing with only 1 slime block in my survival inventory but still had 2 slime blocks. And I could stand in that slime block and get no particle effects when jumped on. This ghost block will disappear once a block update occurs nearby, such as placing a block next to it. And this only happens in survival and you must try this multiple times in order to get the effect.