Running:

/data merge entity @e[type=ravager,limit=1,sort=nearest] {StunTick:40,AttackTick:10}

Will result in the ravager waiting 40 ticks (2 seconds) and then roaring, causing damage, a mob sound and nearby entity knockback. The roar, however, does not do the usual particle effects but, more pressingly, the ravager's mouth doesn't open. This very likely has to do with the mob's internal data (data like pathfinding, targetted entity, etc.) not being updated when the NBT is updated.

There are not any pictures that would make sense to put in support of this.

Steps to replicate:

1. Encounter a ravager.
2. Run the above command.

It would be very much appreciated it if this bug was fixed.