I am looking at https://material.io/design/components/bottom-navigation.html#behavior and there are some notable changes.
- It takes the user to the screen associated with it
- On a visited section, it returns the user to their previous scroll position there
- On the current section, it scrolls the page back to the top and may refresh it
- On Android, the Back button does not navigate between bottom navigation destinations.
So now the recommended approach is more or less exactly how iOS has worked. I am glad at least they describe the preferred behavior because every application behaves differently and even Google apps with bottom tabs are totally inconsistent. I know Material Design is not a “Bible” but the navigation should at least behave consistently.
Of course the new Navigation component doesn’t adhere to the new Material Design spec (yet).