Raising your nutes should only burn it more. Why just one and not the others ? Keep an eye on it to see if it burns more. Being at the front by pump and in rockwool can cause it to hold too much water and nutes. more than the others.

Bend the top if you need to it won't hurt.

Your nutes shouldn't drop like that. I have never seen that much of a drop. Plants take in nutes and give off toxic waste. That's why you need to change rez every 10 to 14 days. Adding more nutes keeps the toxic waste. When your plant rez uses 20 litres of fresh PH water for topups it's time to change it.

Tell us about your water. R/O or distilled or well or tap.

I had a 6 plants that had worse tip burn from nutes and did about the best for me I had.

From the looks of it they will turn out fine. Mybe just one plant that's sensitive to the nutes.
LOC NAR on probation Reviewed by LOC NAR on probation on . frazzled looking skunk #1 I'm currently growing three plants - two skunk #1, and one oasis. now, the one oasis and one of the skunks look just fine so far, but the 'frazzled looking skunk' is beginning to look, well, frazzled. it's taller than the other two, and yellowing around the edges at the top...currently in the first week of flowering, and want to save it if possible. temps in the water are an even 23C / 73F (thanks to an aquarium heater), and room temps are around 26C /78 F daytime, and an admittedly chilly 13C Rating: 5