It'd be great if you could attach pictures that aren't sideways.
We're running an XGS190 over two plants, and I'm currently trying to figure out why we have some yellowish new growth. Looks similar to yours. We added some chelated iron. It'll take a few days to see if that helped. It's hard to push mj into iron toxicity, and I read a few threads that indicated Fe deficiency can be a problem with strong LED lights, so giving it a shot.
Your leaves are taco'ing, which may be why DeeTee said overheating. Leaves curling upward is a signal that they're trying to retain moisture.
Are you running the XGS at full crank? If so, are you following A-51's
guidelines for height?
de, and then 20"-24" above flowering plants in 195w mode.