Earlier quoted context omitted.
Interesting, your take away is that Google is the one with the bug here?
My takeaway is there is no bug. My takeaway is that his test email bounced because he didn't have the reputation Viva does. Emails are handled on a reputation basis, this is why we use email service providers like Sendgrid, Mailgun, Postmark, etc.
What test email? I see no mention of a test email in the blog post. The mail that bounced was the one with the verification link from Viva.