Villagers keep their profession they spawned with after rejoining the world

(Before you read, I want to apologize for my bad english, if there is any)

When I was breaking a job site block from villagers and rejoining my world afterwards, the villagers were having the jobs they spawned with. The trading button didn't appear when I looked at them. I could only make a few unemployed again by placing the job site block I’ve broken before I rejoined the world, because the other blocks were taken by some unemployed villagers (There were unemployed at spawn if you're asking). I maybe could've made more blocks and break them so they get unemployed, but there were blocks like a brewing stand. I must find a nether fortress to make one. You’re probably asking if this doesn’t mean that I should’ve got as many brewing stands as the villager who has its profession. Well you would be right, but there were more villagers with its type than brewing stands for some reason. I think it has to do something with the bug where a villager randomly takes a proffesion and gets unemployed the second after and for some reason the game has saved it. But it's strange because the game should've saved that I’ve broken the job site blocks because it was the last action to the village I did.

Anyways, here is the guide on how to remake this:

• Make a new world and find a village

• Break all job site blocks and lure the villagers into a 2 blocks deep hole (the most effective way is to use a boat with a lead)

• Exit the world

• Load the world again. Every villager who had a profession should have their past look, but you can't trade with them anymore.