How to setup bounced processing on CiviCRM for a Gsuite account?
So I just ran into a similar issue. Our bounce handling stopped a few months ago and nobody noticed. We also use GSuite, and our email address appears in a similar fashion in the log. I thought it looked strange at first too, but since we changed nothing and it went from working to not working, I knew that wasn't the issue. I also tried changing the email account password to see if that would fix the problem.
It turned out that Google turned off access for less secure apps automatically, effectively blocking access to the return email account from CiviCRM. As soon as I toggled that switch, bounce handling started working again. This is the link that worked to turn it back on: https://myaccount.google.com/u/5/lesssecureapps?hl=en