I am really no expert, just ruminating here. The UF looks like what I have seen on some flakes I've smoked, which I see as plume - streaky and sparkly, and not really raised up from the surface of the flake. I would think that if what's on the FVF is raised or mounding on the surface, or spreading through the flakes (rather than on the cut surface) in a way that doesn't coincide with leaf layers or types, it's probably mold rather than plume, especially if it's not sparkly. Is that tobacco pretty dry? I've seen the sparkly plume develop over a relatively short period of time on flakes that were kept in an unsealed tin and drying out.