Name tags are not naming things

I was trying to name my dog, so I got a nametag and spent a level in an anvil. After I hovered over my dog to see it, nothing showed up. I tried it again and still no name.

What I expected to happen was...:

When I named my dog, it should have been named.

What actually happened was...:

Instead, it remained nameless.

Steps to Reproduce:

1. Get a nametag and an anvil.
2. Name the nametag
3. Use the nametag to name a dog
4. Notice that no name is showing up for the dog