What I expected to happen was...:
When i'm playing on the lan or dedicated server with my friend and we are getting far from ourselves, mobs should spawn and leaves should fall down.

What actually happened was...:
Mobs do not spawn, and leaves is not falling down, vines and trees isn't growing.

Steps to Reproduce:
1. Create the lan or dedicated server.
2. Let your friend join to the server.
3. Get away from yourselves.
4. Type "/time set night".
5. Mobs won't spawn, leaves won't fall down, vines and tress isn't growing.
6. (There won't be an issue if you and your friend will render the same chunks.)