Villagers trades are endless and cannot be upgraded

I have created two new trading villagers post 1.16, these are librarians. The villagers created before 1.16 work fine and I am able to trade two books before they lock up, however the villagers created in 1.16 never lock up and I seem unable to get them past a Level 2 villager despite trading their xp bar full a couple times

I am on a Bedrock Realm and this only happens on villagers created after the 1.16 update.