I disagree with the nutrient burn hypothesis. Reason is that there is no sign of leaf tip burn and they are not turned downward. Additionally, your plant is not excessively dark in it's colour. To me, it looks like Calcium and Magnesium issues.
I come to that conclusion based on where it's happening on the plant (mid to upper) and, if you look closely you can see small necrotic spots here and there on the leaves. As well, you can see the beginning stages of chlorosis between the veins of your leaves, which in advanced magnesium deficiency will look like yellow stripes.
The large blotches of necrosis can be a result of over watering damage. Remember, Cannabis plants like soil on the dryer side. They grow in naturally dry climates, Mexico, Afghanistan, Morocco, Africa, India. So they don't like soggy soil with no aeration.
Keep your pH in acceptable range. Anywhere between 5.5 to 6.5 for Coco/Hydroponic, and 6.0 to 7.0 for soil/peat
Conclusion, Pick up a bottle of Calmag. Every nutrient company has one. Follow it's mixing instructions and water with a pH of about 6.2 Calcium is very available at that pH. Mix a gallon of water with the recommended dose of calmag. pH your water to 6.2 and flush the whole gallon through it so you have lots of runoff out the bottom. Let the soil dry out. Then resume your feeding routine but start adding the calmag along side it. Or, you can alternate your application, so one watering is fertilizer. Allow soil to dry out, then water with only calmag, and alternate that routine. always making sure your pH is correct.
Hope this helps and solves the issue! Best of Luck!