What I expected to happen was...:
When I jumped on a bed with a trapdoor or slab above my head, I would fall down at the same speed as normal.
What actually happened was...:
When I jumped on a bed with a trapdoor or slab above my head, I floated temporarily. This doesn't happen when crouching.
Steps to Reproduce:
1. Place a bed down
2. Place a trapdoor or slab on the top half of a block two blocks above the bed
3. Stand on the bed
4. Jump on the bed and you will temporarily hover