invisible mob

At one point the game is running fine in the game until I open my inventory and went back to my game and the mobs and the animal's model stood still. Until night time, I went out and fight some mobs and I saw their model standing still and then I get hit by nothing, I was hit by a skeleton but then the mob kept attack me until I died in my own house. I even left my world and came back and hope it'll fix it but I was wrong. I hope you would fix this. Thanks and have a nice day.
 
 
 
https://twitter.com/i/status/1332002786083364865