Damage wobble does not show the direction of incoming damage in the spectated mob

Summary:
Damage wobble does not show the direction of incoming damage in the spectated mob.

Steps to reproduce:

1. Go to spectator.

/summon villager ~ ~ ~ {Attributes:[{Name:generic.movement_speed,Base:0}]}

1. Follow the villager.

/summon zombie ~ ~ ~ {IsBaby:1b,Attributes:[{Name:generic.attack_damage,Base:0}]}

Observed results:
Damage wobble no shows direction of incoming damage in the spectated mob.

Expected results:
Damage wobble shows direction of incoming damage in the spectated mob.