I've seemingly found a strange bug where Spotify will not scrobble any songs that are titled "Track 1", "Track 2", etc. I first found this when listening to the album Ovalcommers by Oval where every track is titled like that and then went onto last.fm and found that Spotify hadn't scrobbled it whatsoever. I tested this with other Ovalproccess by Oval where the tracks are also titled the same way, as well as with LFO - Track 4 which also did not scrobble. Last.fm does list the tracks as now playing, but does not scrobble them when they finish.
I have tested this on both Android and the desktop player and got the same results.