Yes, there are two thing. First my village is quite big and quite complex so some of villager lost cannot go back to work their job. (Look like worksites detection range is not enough.) Seconds because village is big and there are many bell (I'll assum like bell A = area A, bell B = area B). After some of villager lost from area A and go to area B, Minecraft do something to area A like "Well nobody go to work at this work site in area A, I'll find some unemployee and give a work to them." So ... after I bring villager who lose back I'll find out there's someone work instead.
Seem village don't support many bell in one village.
No, all of them start in 1.14 as I create this world in 1.14.
Edit : I still have save in 1.14.3 prelease 1. I'll find more information and check to make sure about this problem.
Thank you to Syarif Burhan to reply my report, I want to copy what I found from my report.
There are two thing. First my village is quite big and quite complex so some of villager lost cannot go back to work their job. (Look like worksites detection range is not enough.) Seconds because village is big and there are many bell (I'll assume like bell A = area A, bell B = area B). After some of villager lost from area A and go to area B, Minecraft do something to area A like "Well nobody go to work at this work site in area A, I'll find some unemployed and give a work to them." So … after I bring villager who lose back I'll find out there's someone work instead.
Seem village don't support many bell in one village.