The hacker news post doesn’t even link to the article about what’s new in react 18: https://reactjs.org/blog/2022/03/29/react-v18.html#new-stric...

> To help surface these issues, React 18 introduces a new development-only check to Strict Mode. This new check will automatically unmount and remount every component, whenever a component mounts for the first time, restoring the previous state on the second mount.