MP3 playing at half speed. What would cause that?

Factual Questions
1

I have a thumb drive full of MP3s that I listen to in the car through the USB interface. Last night I had to run an errand on the way home from work. The song that was playing was about 2/3 over when I stopped the car. When I came back out of the store and started the car, the MP3 sounded like it was playing at half speed. The song finished, and when the next song started, it sounded perfectly normal. I went back to the previous song and it sounded OK too. I chalked it up to a glitch in the matrix, but seriously, what would have caused something like that? I’ve had this car two and a half years and that’s never happened before.

(2017 Hyundai Sonata, if that makes any difference.)

2

Based on only this information, I don’t think we can say anything other than it’s a bug in the audio player software. Each frame in an MP3 file has a 4-bit field specifying the bitrate (playback speed). This 4-bit value has to be looked up in a table to determine the actual bitrate. Perhaps that table got corrupted (although one would expect it to be in read-only memory). Or the pointer to the table got corrupted. Or some speed-adjustment feature (if there is one) malfunctioned. I doubt even the audio player’s programmers could diagnose the exact problem based only on a report of this behavior.