Why does my 60GB iPod Video stop during some songs?

My 60GB 5th gen iPod Video stops at exactly 2 minutes and 35 seconds in mp3s I’ve synced since yesterday, but no other songs. If a song is shorter than 2 minutes and 35 seconds, it’ll play fine. Something to note is that I’m also using older firmware to play some of those old games. What’s going on?