Is or can UV/Light-bleaching be diminished by a good amount of N in a leaf (dark green)?

Hello fellows ))

Here's the situation:
Weather in central EU's been far too rainy at the end of May which delayed the time to set about 30 homegrown plants into early June. It then became gradially better weather although still some rainy days here & there.

With some of the plants I gave a small amount of liquid fertilizer (all grown on soil already slightly pre-fertilized), which resulted in these plants having dark green slightly N-toxic leafs (not really severely burnt tips) in contrast to the other half of the plants whose leafs are in colour just like stinging nettle.

Didn't instantly put them out into the best spots but in places where they got some shadow from nearby trees at various times of the day - in order to give them about 2 weeks to adapt to the new surroundings.

Then I put them all directly exposed to the sun for most of the day. Furthermore, the weather changed radically to extremely hot + no clouds + no rain. After 2 days the leafs from the brighter non-supplemented plants got bleached, became erratic or weak - like not adjusting themselves in accordance to the sun. After another day it became apparent that most of these bleached leafs are now dying will be lost although the plants are vigorously making new fresh stems.
Most of these dying leafs are actually the big leafs coming from the main-stem.

The N-toxic plants with the dark green leafs are all fine. At first I thought that I just couldn't observe the bleaching because the N-colorization would override that somehow. But, unlike the dying leafs, the dark leafs are still adjusting them towards the sun and appear to be strong. Also, none of them are dying.

Let me further add that I visit them everday & water them every other day or even every day, just like they need, with these temperatures I rather go overboard with water (which is pure rainwater ph 6.0) so can guarantee that the leafs are not dying because of thirst^^
They also don't show the typical heat-stress curled up ridges that appears when a leaf grows too close to a lamp indoors.
Although not a typical outbrand it's 75% indica so EU weather shouldn't be too hot for it now isn't it?^^

So let me ask is there a known correlation between N (or other nutrients) directly prevent lightstress or UV bleaching; or perhaps indirectly by being able to repair the damage done more swiftly?
Because, if you have 15 plans these type & 15 plants of that type, and just the other 15 show exectly the same symptoms but the other none, I think that this greatly rules out any coincidence, isn't it?

buuuuuummmmppp! where are the scientists???

I think you are the scientist and have a sound hypothesis. While there is still a possibility of pure coincidence you make a strong case. It's something I'll keep in mind for next year.

Thanks for your reply, and yes you're right it still may be just coincidence, or perhaps unknown factors chime in as well. I'm really a newbie to this.

Weather for the last 3-4 days was cloudy, even stormy + heavy rain. I've started to supplement mineral fertilizer to the damaged plants, but I suspect it got washed out from the rain. I hope that it gets sunny & hot again so I can start over and also try to observe if the damaged plants newly formed leafs can now withstand excessive direct UV/sunlight.

I still do have 10 younger clones indoors that just formed own roots.
With the other plants my procedure was to keep them indoors for perhaps a month until they formed a certain amount of roots which then justified it to put them into a bigger treehidestyle-bucket or into outdoor soil so they won't run out of water if the sun shines heavy for at least some time.
But maybe I could make it differently now in order to set up a small test.
For example, give 50% of them additional vegging nutrients and keep them strictly indoors; now the other 50% don't get additional nutrients but I could expose them to daylight for a certain amount of time each day, in order to get them to adapt to sunlight/UV light.
And then, once they're both strong/big enough set them equally to the same place and observe which one fare better if weather gets superhot again....