This has been discussed several times: the tracks are not actually corrupted, but prototype normalizer (and compressor?) that got into release by mistake sometimes incorectly determines tune's peak volume and overamplifies it into clipping. Reloading the tune erases its dynamic metadata, removing the effect.

To verify that, you can do one of two things: one is to retrieve the (supposedly corrupted) tune from the player and upload it again. It should sound OK (which means that the file itself was not corrupted). Another is to erase all dynamic metadata (see here and here).

That said, I did notice 2.0b3 decoder complain about bad file format of tunes that previously played OK, or insert a short blip of noise at the end (or perhaps beginning) of some tunes.