I saw an answer on another thread to this same issue:
"Last.fm staff have confirmed that Spotify's internal scrobbling is dysfunctional on the newest desktop Spotify (version 1.0.80) and it also seems to be the case with the newest update of the Android app.
I suggest connecting Last.fm's scrobbler app to your Spotify account. Readthis last.fm announcementfor more information and guidance."
*This answer was originally posted by Sebasty in a different thread.