Music folder copied in full not just changed files

[Cloda]

I am using the Mac version. It works fine to mirror all my files from my selected folders to my designated backup folders on my backup hard drive. The one exception is from my music folder (mostly mp3 and aac files) where it seems to always recopy files that I for certain know have not changed since the previous sync. I have even tried to redo it (e.g. delete the mirror folder and start the mirror sync from scratch). It is a big folder (approx. 400GB) and currently it syncs around 260GB unnecessarily. The only other difference from this and other folders (other than that it is music files) is that it is syncing from a third hard drive to my master copy drive (e.g. not my usual backup hard drive). Apart from this, the software is working great. I will appreciate it if anybody can shed light on what might go on.

[Gianni1962]

To understand what's going on you should look at the preview shown when you press Compare.
May be that these hops from one disk to another make some changes in date/time stamps.