Forgot to add: This happens as the program quits. So the file is actually released and unlocked for the OS to copy, move etc. why can CC not detect that?
Added #2: Contacted Support and was taken through the usual IT Support jumping-through-hoops. I know how to circumvent the problem, but can Adobe solve the actual problem? Can I file some kind of bug report or feature request or what you prefer to call it? I believe that a normal save operation that the local file system can accept also should be respected and followed by the CC file synching. Hate to say it but Google Drive, OneDrive manages this just fine and dandy.