Why lead vocal track "lost" on original audio CD?

One of the songs on my Beatle’s “Sargeant Pepper” CD (original CD, not copy) no longer plays the lead vocal track sung by Paul (using a normal CD player). The instrumental and backing vocal tracks on the song still play fine. It’s only use now is as a karaoke track where I sing the lead vocals (but I hate karaoke!).

What could have happened? Ideas and advice wanted, please. Thanks.

Either one of the stereo channels is disconnected, or your channels are out of phase.
Anyway it’s not a CD issue. :disagree: - that’s simply impossible. Can be a player, cables or amplifier issue.

On what device do you play this CD? A standalone player? A PC drive?

Also this happens often with headphones not properly plugged.