How does this happen--CD defect?

Based on a recommendation in another A'gon thread, I just bought Anne McCue's Roll, a CD that is supposed to have at least a dozen tracks on it. After slapping it in the car player on the way home last night, I started thinking the second song started the same way the first one did, and that was odd. I then started thinking that the second song sounded a lot like the first generally. I then realized the first song was on the CD twice.

Then I got home at determined my copy has the third listed track on it twice, and *nothing* else. God only knows how many CDs I've acquired, but this has never happened before... How exactly, with mass production, does this occur? Anyone know? Is this common? Have I just been lucky?