Affects Version/s: Minecraft 1.6.1, Minecraft 1.6.2
Fix Version/s: None
If you tied up an animal to a fence, then go for the Nether or End, and come back to the Overworld, the lead will disappear
Steps to Reproduce:
1. Tied up an animal to a fence
2. Go to the Nether or End
3. Come back to the Overworld.
Here's a video showing it better: