It is consistent as far as I have been able to tell. I have only d/l mp3 and mpeg file types. Ex:
Coal Chamber - The Ro#4D6C9.mp3
Should be:
Coal Chamber - The Roof is on fire.mp3

What is odd to me is that a random number of the characters at the begining are always correct. Do you think that one of the characters acts as a trigger? For some reason this reminds of the difference between the Hexidecimal and Ocatal systems; I do not however claim to be psychic;-))