Definitely looks a bit like a Cal/Mag deficiency, which from what I've read is relatively common with LED grows.. For mine, I just throw a few extra ml in the res, and I'm usually good, but I'm also only using a 400w, not a beast lol I'm growing an Auto and I add ~20-25ml per 6gal of water, but I think they recommend a bit more for photos since they're not as nute-sensitive..
Another deficiency that causes a similar looking damage to the leaves is manganese deficiency, which I think is usually a pH related..
Regardless, the plants still look amazing!!!!