Villagers are despawning

problem still exists in 1.14.3-pre1

you can manually change the "PersistenceRequired" tag on villagers one by one, by using this command while standing close to villager:
/data modify entity @e[type=!player,limit=1,sort=nearest] PersistenceRequired set value 1b

I think it works, non of my villagers have disappear so far after doing that