So basically, in 1.15.2 if you run while hitting in the ground with your sword, you start to lag. I've had some friends test this so i could make sure that it wasn't just me.

I could not upload the video here because it's to big, so i uploaded it on my YT channel.

Here's a link to the video:

https://www.youtube.com/watch?v=gJ5tP7bL9rI