copying a lot of files from iPhone to PC on sync

[huge]

I have just installed the latest 4.1 beta, but it seems more likely that I'm running into my own ignorance rather than a beta bug, so I'm posting here...

I have a large MM library, Windows 7 64bit, and an iPhone 4. I just tried to make some changes to my auto-sync list and sync my iPhone, and I noticed that it was copying over 400 songs from the iPhone to the PC (these were definitely tracks that already existed in the PC library). I had no idea why it was doing that do I stopped it after about 100 had been copied.

Several things I don't understand about MM's behavior:

-Why it's doing that (and/or what it's doing)
-Which files it is choosing to copy (seems random, some files I've played recently, some probably never)
-How the copied file differs from the original PC file (other than the modified-by date)
-What I can/should do to stop/change this behavior


Sorry if this has been addressed before - I swear I tried to search for it. And if this really should go in the beta forums, let me know - I just didn't think it was all that likely to be a bug.

Thanks for any assistance or info you can provide...

[nohitter151]

As far as I know MM does not copy files from iPhone back to PC automatically, only when the user manually does so.

So how are you sure that the files are being copied back to the PC?