Since Sound Cloud updated on my device on June 3rd it started triggering some kind of play back notification without actual playback, which caused popular "scrobblers" to submit the song to e.g. Last.fm or ListenBrainz.
This happens randomly, but can also be triggered by just starting Sound Cloud without actually starting the playback.
In my case it was using the "Simple Last.fm Scrobbler", but this has also been reported to happen for "Pano Scrobbler". Since this started to happen after a Sound Cloud update I guess it's Sound Cloud misbehaving in some way.
See also discussion at https://community.metabrainz.org/t/431528