This is an issue with Interpolate Audio Waveforms.
This function should be modified such as the anti-aliasing does not occur on samples that have a value of 0 (silence).
I think this is simply related to the anti-aliasing threshold, just like in video games, should be fairly easy to fix, this just has to reach the devs.
Additionally, when you are in the Lower Zone Sample Editor and Interpolate Audio Waveforms is enabled, editing audio can cause the anti-aliasing to turn off until you click somewhere else on the waveform. (Just to remove any confusion, I’m speaking about the new Cubase 12 feature “Smooth waveform drawing”. The issue is only about that and does not concern the smoothing of the samples curve when you zoom in close enough)
How to reproduce that :
With the Select tool, select some audio, then click outside of the selection range but hold your click.
The blue box will disappear but you’ll notice that the content that were selected will not be anti-aliased until you release the click.
Resizing the Lower Zone Sample Editor also causes this issue.
All of the above do not happen with the windowed Sample Editor.
Can you confirm that @Martin.Jirsak ?
Thank you.