Whatever causes it, it's like the little spots undergo whatever process creates a candela wrapper. My theory is that there are water droplets are on the leaves when they're laid out and the droplets magnify the sun and heat the spot on the leaf, thus creating candela-making like conditions. (The process of making candela wrappers involves heating them to "bake in" the chlorophyl).
I think it's simply because QC is lower in Cuba, or maybe they have a philosophy that green spots don't matter while in other countries they filter out the wrapper leaves that get spots on them.