I think Flutter's BottomNavigationBar gratuitously moves outside the Material Design specification.

https://material.io/design/components/bottom-navigation.html#specs

The Specification shows examples of buttons that show and reveal their text, but they do not shift side to side.

The shifting side to side animation on Flutters BNB (type: BottomNavigationBarType.shifting) is distracting, not specified by MD, and confusing for users. (And by users, I mean me. It's not like I've tested it or anything!)

This is personally low priority for me now knowing that there is forward movement on #22882 (comment) but I figured I should post it here for someone to at least consider it.