Might be related but not the same thing as I've experienced. I'm in maps (not navigating, usually just selecting a location) and driving and I get a promote to improve the accuracy (similar to the one where you'd rotate your phone to calibrate the compass).
I am not trying to use AR and the prompt doesn't take me to AR, it just wants to scan the area with the camera and then its done.
[0]https://www.pocket-lint.com/apps/news/google/147956-what-is-...