Placing a boat on a slime block bug (into the air)

When I place a boat on slime blocks, and i jump a couple of times in the boat, and then get in the boat, i get launched in the air.

How to reproduce.

1. Place slime blocks.
2. Place a boat.
3. Get ON the boat and not IN
4. Jump.
5. Get IN the boat.
6. You will be launched in the air.
7. If you get off the boat in survival, you will die by falling damage when you make landfall.

PS: Sorry if i don't got images.