When load the world that saved in 1.14.4-pre7 with 1.14.4, The credibility of the village will be cleared

I just like a Pillager to kill villagers in the village, so I always get the worst price to trade with villagers. But today when I load this world which saved in 1.14.4-pre7 with 1.14.4, I found that some of those villagers replaced their trade suddenly! I feel very surprised. What's wrong with those villagers? Were they took the wrong medicine?