What I expected to happen was...:
Loading chunks containing leashed wolves would not cause them to teleport to you and break free from their leash.

What actually happened was...:
My wolves teleported to me when I loaded the chunks containing them, causing the wolves to teleport to me instead of staying leashed.

Steps to Reproduce:
1. Leash wolves to a fence in the nether.
2. Unload the chunks containing the wolves.
3. Load the chunks again and stand on the ground.

4. The wolves will now teleport to you and drop their leads.