Forgive me if I was wrong but isn't the scan itself pretty going against the claim of Kuuvaki = Light?
The scan here only say "Just as the a beam of light can be split and Kuuvaki can be broken down into distinct elemental force". The keyword here is "Just as". It's a comparison sentence to highlight the trait to be broken into other things. It's not saying Kuuvaki = Beam of Light obviously.
It further said Kuuvaki is the "original state of light". It's not light in itself but can be broken down or made into light as
@Puppet43 said
I am knowledgable about SoL at all. I am just explaning the wording here.