Bug seems to happen only on multiplayer servers, when you lead up a horse, if you go too far away (to where that chunk is no longer loaded), when you come back the lead will be on the ground and the horse will be free. Not exclusive to horses, just an example.

Expected result: I lead a horse to a fence post, he stays there and the lead stays intact.

Actual result: I lead a horse to a fence post, walk too far away, the lead breaks and the horse wanders off.

Steps to reproduce:
1. be on multiplayer server
2. lead a horse to a fence post
3. walk far enough away for the server to stop loading that particular chunk
4. come back and find you lead spinning on the ground and your horse free