Villagers disappearing from iron farm

Recently built a Iron farm and had to get two villagers from a nearby villager, all was going great and it was going great but it was late so I went to bed, and when I woke up I decided to open Minecraft to let my iron farm produce more Iron, to my surprise all my villagers were gone and  its no longer producing any Iron which pretty much means it'll take a while to get two more villagers. It is annoying having to do this because of some bug.

PS: MY BOATS ARE ALSO DISAPPEARING