I had a similar problem with spotty. Sometimes it would only play one song, other times it would play a few seconds of a song and skip to the next song.
Squeezebox Server Spotty seems to have issues using the Ogg Vorbis codec which is Spotify’s codec.
I fixed my issue by going to the Squeezebox Server WebAdmin settings/File Types section. Then look for the Spotty File Format entry and disable the Ogg Voris decoder. Remember to hit Save Settings. This will force the Squeezebox Server to convert the stream to flac.
I am using max2play 2.52 and Squeezebox Server 8.