The sweeping overlay that occurs when you hit a mob with a sword goes from the right side of the screen to the left. This makes sense when the player has the Main Hand option set to "Right", as it complements the way the sword is swinging. However, if the left hand is the main hand, this animation contradicts the sword.

How to replicate:

1. Open a world.
2. Go to {{Settings > Skin Customization...}}
3. Click on Main Hand so that it is set to Left.

1. Get a sword and hit a mob with it.

The video file is too large to upload, so I have put it into a Google Drive link.

https://drive.google.com/file/d/1glvsikxpNvVj7blpeD0JkvOLSYEfqHCW/view?usp=sharing