Not the original poster, but I have been using Spotify for about 3 or so years fairly heavily (free version, not premium), and it still fails to update Discovery Weekly a good 90%+ of the time. The only time I get it to update is when I listen to a wildly different genre (Death metal to K-Pop, for example) and then wait about a month for it to figure out I listened to something different. Only then does it start showing new stuff. Searching around Google, this seems to be a somewhat common issue.