That's pretty common though? I mean isn't that part of the idea of open source? Forking is a pretty central part.

I don't see a problem here. Why should google have to deal with the opinions of a maintainer if they can just maintain their own version. Yeah obviously it would be nice if they'd contribute their changes back to the upstream repo but from a business perspective it's often not worth it.

At my company the inverse of this problem happened way more often: We find a problem but the maintainer just doesn't care. For example the backward-cpp library is a good example where the maintainer just isn't that active in the issues. Why wait for him to respond if you can just fork it and keep on moving.