Ok I will try to clear your confusion.
If you have some components like this
<A>
<B />
</A>
Then on the first load (Reload) log will be
Child B useEffect
Parent A useEffect
Then lets say you navigate to some route and then go to Child component log will be
Child B useEffect
Parent useEffect won’t be called.
As react doc says
you can think of useEffect Hook as componentDidMount, componentDidUpdate, and componentWillUnmount combined.
So all of these lifecycle methods are called after the component is mounted and when component is mounted the child components inside that component have already been mounted and their lifeCycle have been called already
Sandbox to give you an idea how useEffect is called, it has Roster as Parent and Schedule as child. if you navigate to Header and come back to Schedule only it’s useEffect is called.
In your case maybe Parent useEffect is being called when you navigate to child component but that is because of some other reason maybe you have some callback that sets Parent state and thus cause it’s useEffect to be called, but we are talking about how useEffect works in general case
Hope it helps