Athosanswered grow question 6 years ago I can barely see any detail in the video or HID pictures. Heat stress does not produce yellowing like that. You give us no pH, nor EC/PPM, so I can't say for sure if it's pH relates or too much or too little feeding.
Now, yellowing during the stretch is usually due lack of nitrogen; if that it's because lockout, wrong pH or low feeding, I can't say.
If the leaves have also brown spots, then it's not N deficiency, but K deficiency.