Google Play Music cuts let few seconds from tunes

Google Play Music cuts let few seconds from tunes

Started using Google Play Music, tracks downloaded fine, played perfectly for a week then random tracks cut out several seconds before song finishes. I am a dance instructor and this is terrible in a class. I restored to a previous update but one song still ends 6 seconds early. How do I set this and is it worth stopping automatic updates on Google Play if when it does update it messes up my songs?