I just tried adding music with 2.0b3 and every time I try to do it, it adds all the songs I selected twice. I still have everything in Artist/Album playlists, and, for the time being, I was adding the new stuff in that manner as well. (I know -- Soup modes. But I didn't want to play with that just yet, and this still seems like a bug.) I selected an existing artist and it showed the existing album in the right pane. I dragged the new album directory into that right pane. It thought about it for a while, and then showed a dialog box that showed it adding double the number of tracks that existed in that album. When I examined it, I discovered that it had created the playlist with all the music I had expected, and then a duplicate within it.

Uhh. Oops. I'm an idiot. Turns out that emplode was reading the .m3u file I had within that directory that was my playlist for that directory and adding it in addition to the files in the directory. Fair enough, but new since 1.03. It's just a funny story and caveat now, I guess. That and I already typed it in, so you get to read it.