Hi everyone, when i trade with a villager i can't unlock the next-tier items.
I mean, in example, a blacksmith,
When i trade coal for emeralds (T1 trade), i don't unlock the next tier trade as an armor or a diamond pickaxe.
Same with the librarians. I can't get the Name-Tags this way.
Can anyone help me?

You need to complete the latest trade 1-5 times before being able to unlock the next

Unable to reproduce this.

You are supposed to wait for the villager to get regen which takes one trade. I have a simlar problem.