iPod splices bits of songs into other songs

My iPod Touch (2nd generation) has started mixing songs together - splicing in bits of songs into other songs. I listened to an album the other day and during one song, suddenly another song from the album played for about 30 seconds. The iPod still displays the original song and the time keeps going as usual. I restarted the song and the same thing happened. Other songs in the album also played with bits of another song spliced in. I listened to the album again a few days later and the same thing happened, but the splicing happened at different points and with different songs. The songs play fine in iTunes. Has anyone experienced this? How do I fix it?