When you cure a baby zombie villager, he won't give you discounts when he grows up and gets a job, even though villagers you cure always give you massive discounts. Note that I only tested this once, with a naturally-spawned one.

How to replicate:

-Spawn in a baby zombie villager

-cure him

-wait for him to grow up, then link him to any job site block

-he dosen't give discounts :/