Passive Mobs (Animals) will not jump onto blocks when following you.

When passive mobs follow a player with wheat, seeds or carrots in their hands and they are a block lower, they will jump up the blocks to follow you.

The passive mobs will jump, but they don't move forward when they jump, and consistently jump on the same block they are on.

Steps to Reproduce:
1. In a creative world, make a diagonal path, making sure there is a way for a passive mob to reach you
2. Spawn a passive mob with a spawn egg
3. Put the item to get the passive mob to follow you in your hand (Pigs=Carrots, etc...)
4. Observe as the passive mob constantly jumps on the same block over and over, never following you, no matter how far away you are.