Dear CRiR
Good day! Thank you for posting in the Microsoft Community. We'll be happy to help!
First of all, we regret for the inconvenience caused to your work. Based on your description, I have a general understanding of your question, I understand that you are experiencing an issue with flagged emails disappearing in Teams after reviewing the attachment.
Regarding your concern, this is not a bug. When you review the flagged email attachment in Teams, it is only a preview of the email. The actual email is still stored in your mailbox. If you want to keep the attachment in Teams, you can save it to a channel or chat conversation.
To do this, click on the "..." next to the attachment and select "Save As". Then, choose the channel or chat conversation where you want to save the attachment.
Meanwhile, if you still need further help or Imisunderstood yout meaning, please kindly correct me and give me more details so that I can do more research and tests, thanks.
Thank you in advance for your understanding. Your patience and cooperation will be greatly appreciated. I hope for all the best!
Sincerely
Kerry Chen | Community Moderator