nutrient deficient???????

i just woke up this morning to one leaf on my plant looking like this. The rest of the plant/plants look fine. EC is at about .3 and PH is 5.9.

what gives????






grow journal like below

https://www.rollitup.org/grow-journals/257325-super-silver-haze-god-bud.html

first week of real veg by the way