Using New Outlook on Windows for personal email, calendar, and contact management
I'm another sufferer of this infliction. I updated to the new version of Outlook after having a separate issue with the old version which was fixed, but now I have a new [Draft] problem.
Apart from copying sent items into the Draft folder, when I move sent items into my project folder, it will sometimes change them to [Draft] - maybe this occurs when there is also a copy in the Draft folder.
As others have said, this is very confusing as to whether emails have been sent or not. I have looked at the possible solutions mentioned, but none have resolved the issue.
Meanwhile I have reverted to the old version of Outlook and back to the old problem (but that's another story).