I have not followed your thread completely, just now and then, so this is probably a repeat.
When I have unburned powder it is usually a sign of a too light load. Upping the charge a little usually makes it go away. It is pretty common with Unique and I had it with HP38 when I first started using it and was starting pretty light in 45 ACP.
Sorry if this has been covered, or, if you are pretty well up on the charge weight. I have never used the VV powders.
Education teaches you the rules, experience teaches you the exceptions (Plagiarized from Claude Clay)