file quality degrades over time

[songpony]

It seems to me that some of my .kma files are getting progressively worse over time - going from clean graphics to more and more of a "confetti" look. This is a different issue than when they actually record "bad" and look like this from the very beginning - these definitely had been displaying perfectly but are starting to get garbled. Is anyone else seeing this? Is there a resolution to this other than re-recording the specific tracks that "go bad"?