My name is chirag pancahal and from last 2 days i am facing such problem. when i save any file like theme.css then its save as theme.csssdfsdfsdfsdfs and file got blank on server. i am using dreamweaver as a editor.
I get this same issue. Since updating to OS X El Capitan, downloading a new file and then re-uploading causes the old file to be empty and it creates a new file with a bunch of letters and numbers after it. The first time this happened it was on the main stylesheet of the site. I was making several updates in my editor and hitting save each time, then when I refreshed the site, all the styles were gone. When I looked in Cyberduck, the styles.css was empty (0b) and there were seven styles.css-b349af17-96d7-4ef2-8af0-26d8e2fa44af and such.
I discovered that if I save the file on my desktop while editing it, I can save changes to that file and drag the file into cyberduck to overwrite it manually. It seems the file is erased and duplicates are created when using an editor to upload a save.
This is a temporary solution, but it seriously disrupts workflow (especially when employing multiple fixes at once). Please fix this soon.
The transcript shows that the move operation from /dav/template/default.html-94913d8b-326b-4641-a106-783493735923 to /dav/template/default.html is successful (with a 201 response). Please contact mybigcommerce support for further assistance.