Stop modifying the contents of files
One expects the cloud copy of one's files to be exactly the same as the original so please stop modifying Office and other files types to add extra information on synchronising. Makes any system that checksums files impossible and any kind of external sync tech (like robocopy /mir) useless as each time you copy an Office file into OneDrive, OneDrive changes the contents.
Very bad form to change our files without our knowledge!
Files are being updated simply by opening them in Windows. This doesn't happen in web viewing and that is the expected/intuitive behavior. Please fix this very obvious and egregious bug. Thank you for any efforts in doing so.