I have "thumbs up"-ed hundreds of songs, both in the individual stations, and in my "shuffle stations." I thought that songs which I had thumbs upped were losing their thumbs up, so I just re-thumbs'ed them. But now I'm CERTAIN. And no, it's not just that I've thumbsed them in the individual station. I have thumbs-up-ed them in the shuffle stations mode, and some of the songs I KNOW I've done, play without any thumbs designation, and I have to do it again. Why do they keep disappearing from time to time? Not all at once, just some songs over time.  ... View more