Too much light, too much fertiliser. Or too little fertiliser?

magnesium deficiency, epsom salt to rescue, but if you bombard them with light , then maybe cal mag is better or use in combo. epsom brings way quicker result than most calmags, plus while correcting magnesium you can bring calcium toxicity, but if you blast, they need calcium 4sure. thats my personal look.

Sorry, a teaspoon of Epsom salt

Doesn't look like too much light to me. Looks more like the start of a magnesium problem. Likely a soil pH issue, or just a lack of magnesium if you're not using calmag and are growing in Coco Coir. If it was too intense light, it would display at the top of the plant, but your issue is over the entire plant, including the lower, farther away from the light leaves. Magnesium's classic symptoms is yellowing between the veins of the leaf, which is what yours are beginning to do. Magnesium plays a huge role in making plants their green colour. Check soil pH and make sure it's around 6 to 6.5. Always pH your nutrient water or plain water to between those values before you water in, and check your nutrients labels to see if what your using even has magnesium, because some cheap ones don't. You can try adding a teaspoon to a liter/quart of water and pH it and water it in next watering and see if that greens her back up. Also, get yourself the app PPFD Meter and use it to determine your light intensity at the canopy. That plant should be able to handle 900 ppfd at it's current stage of growth. If it's more than 900, dial it back by dimming your light or raising it higher.

yes to much light/ to close to the plants, and maybe giving more water . so dimming bCK THE light, and giving her more to drink will help