I just had it happen on 12c. Same thing as always: a non-reproducible pause in the middle of a song. The hard disk icon was up at the time. It was near the end of a song, and the hard disk had been reading the beginning of the next song into the cache.

If this helps, the little "light" on the hard disk had just gone from white to gray when it happened.

Another thing... This might be my imagination, since I can't reproduce it. But here goes:

When I checked to make sure that it wasn't the MP3 file's problem by rewinding past the skip, it made a funny noise during the rewind. The song was a quiet piece with clean instruments, but during the rewind, there was a brief burst of screeching static, as if the player was trying to send a block of garbage data to the output DAC.

I think (I'm not certain), that the static bit corresponded to the skipped spot in the song. But when I stopped rewinding, the skip was gone and I couldn't reproduce either the skip or the static by rewinding again.

Just in case that helps...

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Tony Fabris