Our users have started seeing this behavior too. At first it was just one user, but now I have two in separate companies using separate networks experiencing the same problem. I tried the "workaround" of switching to Web Mail from Outlook and while it works, it doesn't allow our users to edit the emails to their specifications, primarily because Quickbooks invoice formatting is enforced. We'd like to be able to use Outlook as the email client as before. We're seeing the exact behavior from the original poster, in that edits made in Outlook are not reflected in the final email that is actually sent.