Last November, I wrote:
Switching from Rdio to Apple Music might mean scrobbling to my Last.fm account will be inconsistent, which makes me sad because I’ve been tracking since 2007.
Since then, I add songs, albums, or playlists in Apple Music to my library before I start listening.
With iTunes 18.104.22.168 and Last.fm Scrobbler 2.1.371, I now see songs played from Apple Music are scrobbled, even if they aren’t in my library (including playlists).2 Yay!
Context: Apple Music and Last.fm: Does it Scrobble? — Florian Eckerstorfer