The react component resets accidentally

Is there any special condition, that causes a react component to reset completely (not just re-render)?

What do I mean by reset?

Reverting back ALL STATES to their default values (that given in useState()) and re-running all my useEffect() callbacks (even with empty dependency-list ([])) … LIKE ANOTHER OR A NEW COMPONENT!

This wonderful event happens for one of my components during its lifetime (after a lot of correct re-rendering for this component and other components). I don't know why! And I thought this is an impossible event in React:

export default function Project (props) {
  const [temp, setTemp] = useState(false)
  const tempRef = useRef(false)
  console.debug({ temp }, tempRef)

  useEffect(() => {
    console.debug('INITIALIZATION:', { temp }, tempRef)
    setTemp(true)
    tempRef.current = true
  }, [])

  // ...
}

I'm suspicious of react-router-dom@6.0.0-beta.8 that I used in my project. But I can't change it, because of the scale of the project and a lot of usage of it.

UPDATE: All parents of this component are working as expected. Even after this event (for this component).