Reproduction

1. I've received tons of (200) invitations from neil@be to my personal email address. They are titled "Teams meeting with invitees" and "Teams meeting without invitees". I saved them in a separate folder.
2. Check out Mustang master or neil/invitation-wip
3. Set up my personal email account, as IMAP account, as a new account in a fresh Mustang profile.
4. Open that folder with the invitations
5. Click on the invitations

Actual result

• I see the email body, which sometimes shows a Teams invitation as HTML email, and sometimes is completely empty
• No event data is shown, at all

Expected result

• The event data shows as a header below the email header, above the email body.
• I can accept or decline the event
• If I accept the event, it's placed in my calendar