Sorry, I have no clue what you are talking about then.
Folders (syncthing folders not filesystem folders) need to have the same name, hence I am not sure how you are trying to connect two different folders together.
If you move a file in F1 while F2 is syncing it’s expected that it will disappear (because it did disappear from F1 and reappeared somewhere else, hence this new location is now being synced).
If you modify any files on F2, F1 will refuse to sync with it (because F2’s version is now newer), and this is expected.
It might continue to work (not sure) if you for example and new files, but it will definitely not update the files you moved.