Some mob and sombies would not damage you at demo mode

Put the summary of the bug you're having here

What I expected to happen was...:
When I am attacking mob like zombies and spider or even wolf/dog, they should attack me and cause damage to me.

What actually happened was...:
Several monster wont attack me

Steps to Reproduce:
1. Wait till night, or find any zombie or spider
2. don't attack them, just come close (it is actually should aggro right?)
3. try to attack them to see if they are going to attack u back

4. if you have a dog or dogs, they will not attacking neither tamed or not. they'll just jumping and cause no damage.