Sync redownloading a few unmodified files

A few of my media files on ACD are being redownloaded at every rclone sync even though I have not altered them in any way. What could the cause of this be?

If you run with -v then rclone will tell you why it is downloading the files.

If you could post the output of that with the command line you are using, that would be helpful to diagnose what is going on.