Bed disappear/invisible when log in to world

Whenever I log into world after save and quit I found that my iron farm isn’t working and 10 of 20 bed have become invisible. I can still break the bed but the villager can’t working. I think it is because of the bed. But when i place it back the farm start working again. But it annoyed me that everytime i log into the world the bed just keep become invisible.