Baby villagers cannot be summoned properly with proper command

When I run the command:"/summon villager ~~~ minecraft:as_baby", it summoned an adult villager instead of a baby villager. But other mobs(such as zombies) don't have the same issue(i.e: when I run the command:"/summon zombie ~~~ minecraft:as_baby", it summoned a baby zombie and when I killed it, it will give me proper exps)