I have backed up my bootcamp a few times successfully and the other day I actually needed the backup to restore, so I did so without any issues. Now After getting the windows to work again I wanted to go back to Catalina and make a fresh updated backup. But this time the backup starts scanning and then quickly switches to a message “Backup was created Successfully” and the file is just a few bytes in file size.
I made a 40 sec. video showing what I am seeing