This can happen when volume is being adjusted before an earlier track, having a different audio stream, is completely finished.
Nokia is investigating this issue and will do some corrective actions but until then, to preventing this issue to happen, the user can do the following things:
1. Try to avoid having both mono and stereo songs on playlist.
- In the mixing of stereo and mono mp3 files, there will be a mix of multiple audio streams.
- Whether the audio file is mono or stereo, can be checked by using PC and e.g. VLC player, Mediainfo, etc. program that displays technical information about media files.
2. Try to avoid adjusting volume right after skipping songs (if you have both mono and stereo tracks on playlist).
Quick workaround: Rebooting the device.