As a medium mob warden will not auto-jump

The bug

As a medium mob warden will not auto-jump.

Steps to reproduce

1. Summon a warden.

2. Try to push it up the hill.

3. Found that it does not auto-jump.

Unaffected medium mobs

1. Llama

2. Trader llama

3. Horse

4. Donkey

5. Mule

6. Skeleton horse

7. Zombie horse

8. Enderman