Teleporting a leash knot does not update its hitbox. The hitbox remains at its old position.
This also happens when directly changing the Pos tag value using the /data command.
- Leash an animal to a fence
- Teleport the leash knot to a second fence
- Enable hitboxes being shown: F3 + B
→ The hitbox is shown at the old position, hitting it destroys the leash knot
MC-104582, looks like this might still be accurate.