Song plays fine until saved to playlist

[Tizzwozz]

Hi,
I've just been listening to an album and saved a couple of the songs to my playlists (which also saved it to my device) but when I've gone to listen to them from my playlist the full tune isn't there. One only plays for 10 secs (just the intro), another has a minute with the middle cut out??
Any ideas? I have loads of tunes saved to my playlists and never had a problem before??