A Drowned was spawned in by a certain command, but was unresponsive to the player...

[The world is in survival, gamerule mobgriefing was set to true, Cheats was turned on]

Command used for spawning drowned-

/summon drowned ~ ~ ~ {Invulnerable:1,PersistenceRequired:1,Silent:1,CanPickUpLoot:1b,ActiveEffects:[

{Id:18,Amplifier:0,Duration:999999}

]}

It is guaranteed that the drowned can see the player, but won't attack it

 

EDIT: The Drowned is attacking baby turtles and smashing eggs, but not attacking the player...

Screenshots given below