Given a slime block with a lower half slab of any type under it (or an upper half slab of any type over it), the half slab is moved along with the slime block when the slime is pushed in a horizontal direction by a piston. This is unintuitive, does not seem to be intended, and it really limits the number of independently movable slime block structures per chunk.

What I expected to happen was...:
The slab should not have been moved in either case, since it did not actually "touch" the slime block in a physical/graphical sense.

What actually happened was...:
Both of the slabs stuck with the slime block, creating the impression of being moved by magic.

Steps to Reproduce:
1. Place a half slab directly on the ground
2. Place a slime block directly over it
3. Place a piston (sticky or not) right next to and in the same height as the slime block so that the piston's head is facing towards the slime
4. Activate the piston