I’ve seen this raised a million times but all the topics are closed. Scrobbling doesn’t happen live, it seems to happen whenever I switched from playing on my Sonos speakers via Spotify to another device (i.e. phone, laptop). If I play music only on my speakers for a week it will never scrobble anything.
When it does scrobble if you switch away, as mentioned it only scrobbles the last 50 tracks, meaning I lose hundreds if not thousands of scrobbles a month.
This may seem silly, but I’ve used last.fm since 2008 and I really enjoy keeping a proper back catalog of music throughout my life...I would really like this to work properly.