Hey there
@MrRaid
Doesn't look to me like nutrient on leaf, since it looks like from the pics it's affecting multiple leaves around the plant. My guess would be nutrient overload. Maybe that one plant is just a weaker pheno and can't take as much nutrient early on as the others? I would try flushing with some pH balanced water and skip the feed for that plant for a week and see if it improves. Or you could just keep going as the plant otherwise looks healthy, it'll probably outgrow the issue and just end up a smaller plant than the others.
In anycase, goodluck! I'm sure it'll still be beautiful in the end!