The Bug:

Warden stays idle, does not care about the player or vibrations despite being right next to a player. I used a /summon minecraft:warden for this, but this does not happen for every warden, so I am not sure how to reproduce this or what is happening here.

I will attach videos and also put a video with the NBT of the warden (it does not have NoAI)

Observed Behavior: 

The Warden senses vibrations and is attacked by the player yet does not roar or attempt to attack the player.

Expected Behavior:

The warden senses vibration and will attack and roar at the player in attempt to hurt them.

Attached Videos:

Video 1  click

Video 2 click

Video 3 click