Dr. Sassi, thank you so much, as always, for your efforts.
I worked around the issue, to get through my deadline. But I haven't solved the actual problem; which I believe may be somewhat related to the actual geometry object, which is acting as the surface emitter.
I'm attempting to build a version of that project, with a proxy object serving the same purpose, but I'm finding the results are different enough, to likely not warrant the effort.
Complicating matters (as you certainly know) is that the final banding results don't entirely manifest until the whole particle system is cached, and even then, only at final render.
I'll continue to see whether I can create a scenario which illustrates the issue, then I'll post the example project.
As a side-note: I've come to find an serious issue between the "sphere instances" and "optimized spheres" as they relate to rendered particles.
When I view the optimized sphere particles through the RS viewport, they appear as expected; just like the sphere instances.
However, upon final render, the optimized spheres tend to have an offset from the emission source, by a noticeable amount of pixels.
I'm aware that the Maxon documentation warns that there may be certain limitations for the optimized spheres, but the fact that the issue only manifests in final render, makes it extremely time-consuming to find.
But this is likely more a Redshift issue, being that it directly relates to their render tag, right?