Bigbug
Almost. The script looks for unread messages in the inbox and then tries to process. If for whatever reason processing fails (usually an unknown sender, but could also be a corrupt message or anything else), the message is marked as read and flagged for follow up. If the message is OK & processing succeeds, the message is moved to the ITFlow folder.
In my view, the email parser is functional in the current state: If you want a message parsed, leave it unread. The only time I want to spend on it at this point is getting it to work with *OAuth2.