Social Zombies not affected by /gamerule doMobSpawning

1. Create new world
2. /gamerule doMobSpawning false
3. /kill @e[type=!Player]
4.

{{/summon Zombie ~ ~1 ~ {Attributes:[{Name:zombie.spawnReinforcements,Base:1.0d}]}

5. Punch the zombie to death, observe others spawn