Spotify does not normalize a song if it is succeeded by the next track on the album it originates from. This would be expected within the "album view" context, but unfortunately it applies to Liked Songs and playlists as well. This is not desirable as it causes inconsistent volume levels within playlists unrelated to the original album.
It seems Spotify's current implementation uses the next song in queue to determine whether to normalize the current song, this can be speculated as the problem can be avoided by enabling shuffle.
Please make an implementation or option for normalization that does not enforce the volume level of the album of origin in unrelated contexts such as playlists or Liked Songs.