I'm also having this issue in version 1.7.10, when I finally found a long lost "dog", as you can see on my video here (it is in portuguese, sorry, but you will realize what is happening just by watching): https://youtu.be/VsqWcAW6C7k?t=6m3s
The version is modded, but the issue doesn't seem to have any relations with the mods themselves.
I'm also having this issue in version 1.7.10, when I finally found a long lost "dog", as you can see on my video here (it is in portuguese, sorry, but you will realize what is happening just by watching): https://youtu.be/VsqWcAW6C7k?t=6m3s
The version is modded, but the issue doesn't seem to have any relations with the mods themselves.