Steps to reproduce.
1. Log into Spotify on a desktop.
2. Ensure your settings are set up to scrobble to last.fm
3. Play a track.
4. With the same Spotify account, connect to the android app on a separate device.
5. Ensure that the android settings are set to scrobble to last.fm.
6. Choose to control the desktop plays through the Android app.
What should happen.
Tracks played are scrobbled to last.fm once per play.
Each track is scrobbled twice, once through the desktop app and once through the Android app.
If the Android app is using connect, it should be able to work out if scrobbling is already happening on the desktop account. I can't imagine a valid usecase where you'd actually want two scrobbles for each track in this scenario.