From the link you provided, it's a bug with WINE's MP3 decoder. How is that intentional?

Wine's mp3 decoder doesn't work in some cases, including some mp3 files by Spotify's partners[1]. Because the decoder didn't work for some mp3 files, they are actively blocking wine's mp3 decoder for all mp3 files.

[1] I agree this is a pretty solid business reason to block it, but it's still intentional.

The workaround [1] seem to work pretty good so far. No crashes, but it does go into a (recoverable) loop if you pull the slider to the end of a track.

[1] http://getsatisfaction.com/spotify/topics/spotify_under_wine...