Random skipping on Clip Zip

[korn36]

I have a Clip Zip, and I have a problem:
When listening to songs in AAC or FLAC format, they skip to next one randomly (OGG plays, but it randomly drops some samples while playback).
In OF, this does not happen.
I don't use a microsd card; I only use internal memory of the player.
Here is output of "disk info" in debug menu:

"view HW info" shows that this player has "AMSV2 variant 1".
Anyone encountered this issue?
Does someone have a fix?