boat breaks like in older versions (into planks and sticks)

boat breaks like in older versions (into planks and sticks)

What I expected to happen was...
the boat would break into a boat or would not break at all

What actually happened was...
the boat broke into 3 wooden planks and 2 sticks

Steps to Reproduce:
1. put a sticky piston one block into the ground and place a slime block on top
2. put a boat on top and power the piston however you want