To be fair I think Polygon have misunderstood the email.
Calling it "second run Stadia PC RPG" implies Microsoft thought it was going to launch as a Stadia exclusive for it's first run. This was back in 2020 when Stadia was still a thing, and trying to sign up exclusives.
That doesn't mean Microsoft underestimated it, but that it thought it'd already have had a run on Stadia which would make it less likely to be an important title for Microsoft.