We added a new feature for saving to systems with Unicode characters for non-english languages (like Chinese, Greek, etc.). It requires FAB 3000 to save the file to a temporary place before copying to the Unicode system. To disable this feature, go to menu: Setup / Options... Uncheck the very bottom option "Perform File Buffering for Unicode/Network", and press OK.
Now you should be able to correctly save.
I will review the cause of the strange behavior and resolve it.