I am also having this problem, however I am using a slightly different setup to most. I am publishing from a Gapps email address. When I manually send an email to this account, it gets posted without any problems. However I am also sending emails to this account from a Google Docs spreadsheet using a Google Script (I’m using the spreadsheet to automatically generate the html code that I want to get posted). Any emails sent from the spreadsheet get flagged as possible XSS attacks (and I have added the Gapps account to the approved ‘users’ in Postie).
