I connected my iPod to my PC for the first time in maybe a few weeks. I hadn't added anything to my iTunes Library—whenever I do that, I connect the iPod and sync. Despite this, iTunes decided it was necessary to "update" some 1,000 tracks (of about 3,600—not all of them) on the iPod. Why is this? The only thing I had done prior to this was update iTunes to 18.104.22.168. Does this really require the "updating" of a third of my music collection?