If i'm pushed to a 2 block with a normal piston then i go swimming

 

What I expected to happen was...:
Push me away/ up

What actually happened was...:
Let me go swim, on ground

Steps to Reproduce:
1) make a cave with 2 blocks high and make the ceiling normal pistons,

2) activer the normal piston when your in it, with redstone.

3) go in F5 and look yourself swimming in no water.