I don't know what could be reason to cause leaves to get orange/brownish spots/marks. There is no bugs and ph is controlled to be 6.3 to 6.5. Still investigating the problem.
The Browning looks like a nutrient deficiency, PH is too high for coco should be between 5.5 and 6.2 with 5.8 regarded as the sweet spot. The ec is also little high 1.8 to 2.2 from feed charts.looking back through the veg stage in sure by having such a high ec and PH, the plant has nutrient burn and locked out.