Because Meta, meaning OPs here, doesn’t use ”why” as Google wants? I did some expriences and even the context stays same, using different sentences changes search results. As expected.
And… personal search history is big and not so good thing. My results are quite often pointing somewhere else than to Meta, because I’m doing searches here, not via Google.
Yes. Still Discourse may have some issues with Google, and that may or may not come from ”forum status” where Google isn’t reacting to forums same way as to ordinary website. Or there is some technically issues — even that is the reason quite rarely.