It's the iPod. I've just recently been having the exact same problem. It never happened last year, even in the most bitter cold, yet it has happened several times in the past month. I have mine set to play all of the tunes in alphabetical order (3 months straight with no repeats), and have found that it takes longer to come on, and when it does, it defaults to showing the first song in alphabetical order. It will keep this song displayed for the entirety of the trip, even though it plays the song it should be playing in the order it should play it in (ex: will display Absolutely Sweet Marie, but will play Toad). Cycling the on/off does nothing. I have to power down the car for a while, then power back on again for it to switch back to being normal.
I think I have fixed the issue by waiting for the iPOD to completely connect before doing anything to it, such as powering it off, changing the tune, etc. If it is allowed to completely connect, no issue. If I interrupt it, issue.