I believe that the 32nd Verlinden F-16 set is an older piece, it's been around for quite awhile. In the beginning, Verlinden resin (as well as most resin) was kinda ugly. As the technology progressed, though, their stuff got much better. Really nice, as a matter of fact.
The master itself could have also been somewhat poorly done, by today's standards, anyway. The fidelity of detail present in the resin of the last several years is amazing compared to what was being done at the time this set was first produced.
In general, the old resin isn't as nice as the new stuff, and also; the molds used to produce resin castings are only usable for so many pours, then they begin to break down. This may also have improved over the years, but they will still need to be replaced. Perhaps you got a set that was poured toward the end of the mold's usefullness. Or, perhaps the master (or masters) is getting worn from so many cycles.
I think it could be a combination of all or some of this, but the root of the problem is most likely the age of the product. It's truly a product of it's time.
Fade to Black...