I was editing a wav track with Melodyne-vst and accidentally clicked the scratch pad button. After that, the waveforms appeared twice or more often in Melodyne (but not in the track). I couldn't clean up the sound file either. The cleanup only works with an external program like Audacity. Of course, the Melodyne editing was then lost.
If you want to reproduce the error, create an audio track, open it in Melodyne, close Melodyne again so that the green marking remains, then click on the scatch pad, close the scatch pad, open the track again in Melodye and - Tata! - the waveform is duplicated, multiple or corrupted. And now?
Best regards, Klaus