Crouching does not work while standing on an entity at exactly y = 64

Summary

When crouching while standing on an entity (such as a boat, happy ghast, etc.), if the player is at standing exactly y=64, the crouching animation will not show and the player can move at normal walking speeds. The player will still not walk off the entity as is normal.

Steps to Reproduce

With a boat:

1. Go to a location at y=63

2. Place an Amethyst Cluster on the ground

3. Place a boat on top of the Amethyst Cluster

4. Jump on the boat (so that the player is at y=64)

5. Press the crouch button

With a happy ghast:

1. Go to a location at y=60

2. Summon a happy ghast, place a harness on it, and get on it

3. Fly down to the ground and get off the happy ghast (so that the player is standing on the ghast at y=64)

4. Press the crouch button