screen bug with the sword

I remember that before a sword could break a block now it has changed but I will not talk about the antiquity if not a bug or error as they call it good the bug is when the sword touches a block ie break the block with the sword when trying to destroy the block with the sword the screen is traversed for about 1 second is not that my computer is not a potato my computer is a PC gamer returning to the screen error when it is traversed, but nothing happens to the fps is say that it does not lower the fps the screen when it is traversed is annoying because you delay a 1 second when you try to kill a mob or other good I hope they fix the bug if there is an error that I put in this comment tell me