Horses can hang form leads and the lead will not break or disconnect.

If you connect a horse with a lead to a post, then push the horse off an edge to where the horse cannot touch the ground, they will hang there in the air. You can also drag them into the air if you are holding the lead in your hand.

*What I expected to happen was that the lead would disconnect and the horses would fall.
Describe what you thought should happen here: I feel that the lead should disconnect if they get to far away within a certain time. I understand that this is tricky because that would affect the horses being attached to post with a lead.

*What actually happened was the horses just hung in the air and bounced around.
Describe what happened here: When the horses were pushed off the edge, they hung in the air with a lead attaching them to a post.

Steps to Reproduce:
1. Make a decent sized platform above the ground(did not take measurements, but 50 blocks would be plenty).
2. Spawn a horse a few. Place a single fence post near the edge of the platform.
3. Connect the horses to the fence post using a lead and push the horses over the edge. If you attach a horse to a lead with the other end in your hand, fly up into the air and the horse will come with you.