Certain mobs still move when more than 32 blocks away from the player

The bug

Ghasts, magma cubes, slimes, fish [...] and all the mob that don't use the traditional random strolling type movement that normal mobs use, can move outside the 32 blocks of range causing lag.

How to reproduce

1. Spawn some zombies and some slimes 
2. Go in spectator mode
   → Zombies can't move, slimes can