In an existing world hostile mobs were moving naturally, but passive mobs except for a few would not move even when hit.
Needs further testing
~~Updated~~
Mobs from spawn eggs seem to act normally
Hostile mobs spawning at night, and moving
Could be an issue with pre-generated mobs?
CHRISTIAN M TAYLOR
In an existing world hostile mobs were moving naturally, but passive mobs except for a few would not move even when hit.
Needs further testing
~~Updated~~
Mobs from spawn eggs seem to act normally
Hostile mobs spawning at night, and moving
Could be an issue with pre-generated mobs?