Lagging/delay after update while multiplayer

Hello Mojang, I want to report about lagging and delay when playing multiplayer with my friend in his world, I experienced this after your latest update, I don't know if it's because of the host signal or the world, it's possible that the world is buggy because my friend who owns the world said so himself, oh yeah, initially this was also caused when my friend was about to take the ender dragon's head then for some reason he suddenly force closed the game, and so did I when I tried it, this is funny because we joked about Herobrine before but it's impossible, here I can't provide screen evidence because it's indeed lagging, thank you Mojang