I think Frenetic mentioned to me once about something that I guess would be called "Voxel Temporal Anti-aliasing".
I tried to implement it but couldn't get it working - but now that I think about it - I only tried it for the lowest level voxels (highest res).
Majority of the flickering actually occurs at mid-level.
I think the way to implement it is to fade in/fade out the color of adjacent voxels based on the position of the object within each voxel so that it smoothly interpolates instead of jumping from 0 to 1.
I'm trying to re-attempt this but I just realised I don't actually know how to track how much each part of an object is within a voxel. Originally I had thought of accessing the geometry shader stage of my voxelization and storing the difference between the position of each voxel and triangle.
Then I set my input for alpha into the voxel texture as 1-density. But this doesn't help the flickering - it actually makes it worse because when my alpha value is set to one, it reduces the color bleeding of the entire scene. Thus it flickers between color bleeding and little color bleeding - leading to flashing.