Curious about this light; the description says plastic, and all of the SK-68s I've seen have plastic lenses. Based on djozz's testing here:
https://budgetlightforum.com/t/-/31542?page=2#comment-719507
...plastic lenses are quite good at blocking true UV emissions. I'm betting that the UV is being blocked by the lens and all you are seeing is the fluorescence from the low-level visible blue light that isn't blocked.
This would be cool if you could get a glass replacement lens for an SK-68 though...