So now iTunes syncs again and again the same movie ....

So all of a sudden (started 3 or 4 days ago), every time I plug my iPad into my iMac, iTunes launches and the very same movie syncs, Also a bunch of songs. iTunes copies them to my iPad from my iMac. I checked and they are definitely on my iPad. So why all of a sudden this odd behavior? My phone doesn't do that. Both are running same iOS9.latest.