Die mobs[villagers] reapear after reentering a world and die installing making imposible to place blocks in that spot

I was trying to place a block next to a fence, that was put in a different version, but when i tried to finish it in 19w13b, it did not work
After a bit of research, I have notice that every time i enter the world, a villager that i kill reapear in that sopt and instanly dies, so I think It is a bugs cause by the next systeme use for when mobs dies