Hi, there are numerous threads on the same issue if you search, and they all start with the same response, which is to do a manual run and check the Differences window for why the files are being copied again. There must be differences in the properties being reported to Pro or it wouldn't be copying them (or proposing to). Unfortunately we can't see from here what they are, so you have to tell us. For example, a common issue is that Source files actually are being modified by indexing or search processes. Another is FTP servers (and/or NAS devices not storing the LastModified date/time stamp correctly on the Destination.
But as we've no info on the devices/services in use, nor what differences are being detected. it's hard to speculate.
But as we've no info on the devices/services in use, nor what differences are being detected. it's hard to speculate.