This is pretty obscure bug (or bugs) that I noticed while testing the addition of context (right-click) selected move and copy of folders, bug 1831759.

Moving a virtual (search) folder within Local Folders that are maildir based, the move does not occur. See this error on console:

[Parent 1054589, Main Thread] WARNING: NS_ENSURE_SUCCESS(rv, rv) failed with result 0x80520012 (NS_ERROR_FILE_NOT_FOUND): file /home/gene/mozilla2/comm/mailnews/local/src/nsMsgMaildirStore.cpp:438
JavaScript error: chrome://messenger/content/about3Pane.js, line 2458: NS_ERROR_FILE_NOT_FOUND: Component returned failure code: 0x80520012 (NS_ERROR_FILE_NOT_FOUND) [nsIMsgCopyService.copyFolder]

Move of virtual folder works OK on mbox based Local Folders.

When moving a virtual folder within an imap account/server, you can move it to any folder one time within a session. If you try to move it more than once back to the same folder, often the move does not occur. It also sometimes hits an "ENSURE_SUCCESS(rv, rv) here:
https://searchfox.org/comm-central/rev/a8a527d3a13553a492016f9dba13f09c758e1afc/mailnews/imap/src/nsImapMailFolder.cpp#7383
failing with NS_ERROR_FILE_ALREADY_EXISTS which will prevent the move. It works better with that line commented out, but doesn't really fix the problem.
Restarting tb clears the confusion and you can move the virtual folder anywhere within the same imap account again one time.

This doesn't seem to be caused by my bug 1831759 changes since I see the same problem using d&d of the virtual folder.

supernova related?

(In reply to Wayne Mery (:wsmwk) from comment #1)

supernova related?

I don't think so. I just tried it with 102 and see the same thing.