spawning zombies villager with the name is spawn only with the command does not work

what should really happen in minecraft:

zombies should randomly spawn, but this doesn't happen if you put a custom name

Steps to reproduce the bug:

(-)create new world 

➖  /give @a minecraft:command_block

➖  summon minecraft:zombie_villager (normal)

➖  /summon minecraft:zombie_villager ~ ~1 ~ {PersistenceRequired:1b,CanBreakDoors:1b,CustomName:'

{"text":"bug?","color":"dark_red","bold":true}

',VillagerData:{level:1}} (name)

-attention:
my english is not much spoken,
I use google translator so the translations will not be 100%