Damaging a mob on the same tick it is summoned does not cause it to aggro on its attacker

Damaging a mob on the same tick it is summoned does not cause it to aggro on its attacker.

To reproduce

1. Ensure you are not wearing any armor

2. /effect give @s minecraft:invisibility infinite 0 true

3. Go into survival

4. /tick freeze

5. /summon creeper ^ ^1 ^3 {ExplosionRadius:0,CustomName:"Older",CustomNameVisible:1b}

6. /tick step

7. Look slightly to the right or left

8. /summon creeper ^ ^1 ^3 {ExplosionRadius:0,CustomName:"Younger",CustomNameVisible:1b}

9. Punch both creepers with your fist

10. Step back from them a few blocks

11. /tick unfreeze

Note how only the creeper which has existed for 1 tick gains aggro on you.

Expected behavior

Both creepers would gain aggro on you.

Note

This two-mob setup will not work for zombies, blazes and other mobs which call others to the fight, since the older mob will pas its aggro to the younger one.