Player teleports to the top when crushed by a piston head

The bug

When I get crushed by a piston head, in a second I teleport on the top of the piston head, instead of still being crushed in it.

Steps to reproduce

• Place any non-transparent block and redstone block like in the picture.
• Go to the place where the crosshair is directed in the first image.
• Place the piston as shown in the second image.
• ???
• You will be teleported to the top of the piston head.