Cured baby villagers have no discount

I had a baby zombie villager in my home, after he was cured and grown up he doesn't have the nice discounts.

Steps to Reproduce:

1. Spawn a baby zombie villager
2. Throw a splash potion of weakness at it and feed it a golden apple
3. Wait for the baby villager to grow up
4. Once it has grown up, give it a profession and open its trading UI

Observed Results:
The villager offers no discount on trades.

Expected Results:
The villager should offer discounted trades.