What is the social media person supposed to say in this case? "we're working on a blog post about Stadia shutting down that'll be released in 2 months"? Even if Phil Harrison himself were the one running that Twitter account, he probably knew it was destined to shut down but didn't have anything official on when or the details of the shutdown.
Something evasive in the vein of "Stadia represents a significant investment and Google has not announced any plans to scale back Stadia. We can't comment on rumours and speculation."
There are also those who knew it was at risk and in danger but thought that it could be saved with hard work and a little luck and were working toward that end.