This ONLY affects my windows 10 pc in both realm and local world, my android phone works fine.

When standing on top of a slimeblock and being pushed upwards by a piston, usually I get launched upwards in the air due to the slimeblock bounce. 

Now when doing the same thing I get offset a block in a horisontal direction before being pushed upwards.

Notable is the fact that if regular "non bouncy" blocks are next to the slime block I will be placed on one of these and not recieve any vertical momentum at all. However if its only air next to the slimeblock it will still launch you upwards but a block offset from where you were originally standing