VILLAGERS BECOME INVISIBLE

When I get into the game I see my villagers just have completely disappeared or become invisible, but I know they are there because I see their energy when trying to lay on a bed but they can't sleep, I also hear them making their sounds but they're just invisible. Ever since the last update this problem has been happening to many of us, once I log off and come back in some of the villagers reappear but the rest are still invisible and tired because they cannot sleep. Please solve this issue.