would love to help m8, but kind of hard to get much idea of what's going on from that pix ... try and take a few new pix, but take them when the lights are out so we can get a better idea of the true color of the plants..
the problem with your pix is that the lights tend to make everything look a bit orange, and it's super hard to diagnose problems when the pix are washed out with orange color like that if you know what i mean..
also, try and take some pix of the problem area, and a few of the entire plant.. the more pix obviously the more we'll be able to help..
fyi, to take pix with the lights off, just wait for lights out time, then take a few right after the lights go out..