Put the summary of the bug you're having here
What I expected to happen was
The game to run normally.
What actually happened was...:
The game started lagging a lot.
Steps to Reproduce:
1. Play a saved file after updating the game.
2. after the world loads....
3. ...it starts lagging
Environment
It happens in the Java version of Minecraft
Please do not mark unreleased versions as affected.
You don't have access to them yet.