Using classic Outlook for Windows in business environments
Thank you for your description of the "workaround" which worked for me. Like others on this thread, this issue appeared for me after I switched from POP to IMAP. It appears to be related to reading a message in Outlook (which changes its status from unread to read), but the change in status hasn't been forwarded to the server version yet. It seems to be that switching to another message (or in my case, switching to a message in another folder) "frees up" the message to synchronize between Outlook and server; so that upon returning to message, the message can be moved without the notice.
Unlike other posts suggest, this appears NOT to be related to Exchange (since I do not have any exchange accounts), but IS related to IMAP.