Some strains are dark , others not so much.
I've never aimed for lime green leaves .
You're correct that high temps will cause more uptake and plants tend to take more N when it's available.
But the original pictures show no signs of having too much N or been odd in colour, simply healthy plants.
Don't make the mistake of thinking you know more than a nutrient company at providing a balanced feed .
The reason they are lighter in early flower is because the energy is going into stretch and new bud sites and the nutrient uptake doesn't keep up with the rapid development.
Then that rapid growth steadies and the nutrient uptake catches up and your leaves darken.
You are imagining problems that don't exist as far as I can see
