Hello fellow gardener.
I tend to talk for too long so I'll try and keep it super short. I believe you're looking at a potassium and Calcium/mag deficiency on this specific girl. The top affected leaves look just like a potassium deficiency, with the browning/yellowing working it's way from the outside in on your newest fans. When you panned down in the video I saw the specks on the lower section. This could be the result of residual salts left by a foliar spray used that burned on the leaves surface (splash back), but I feel you're still looking at potassium and probably a Cal/mag deficiency coming up the rear, as lack K affects top and bottom foliage. With her specifically, I suggest tailoring a special feed for her for 1-2 weeks. In her feed I would simply cut my Nitrogen and up the P/K/Cal-Mag at 6.2-6.4pH where it's taken up by the plant optimally. Look for a good amount of run-off (25-30%) to ensure you're washing out anything that may be mal-adjusting your soil and interrupting the intake of the new nutrients that you're adding ("flush through"). Lastly, when it comes down too it, pH is key. If your soil pH and RO are coming back really high/low, some nutrients may be experiencing a semi-lockout while others are being taken too quickly (Darker green leaves on her middle section in the video. Looks like excess Nitrogen). Things like zinc, iron and copper can interrupt the intake of P/K/Cal and are usually added and work in conjunction with your Nitrogen supplement.
Balance pH, cut Nitrogen (zinc, copper, iron), up P/K/Cal-mag over 2-3 feeds and I'm positive she will start to recover. Rest of the girls look great, she's just the odd one out. There's always one, haha.
Hope that wasn't TOO long. Drop me a PM if you'd like to speak further or about what's taken up @ what pH, I'll be kicking around. Cheers and good luck my friend👍😉