To begin, I'd like to say, "Isn't it a trip how many differnt things that can happen that defy normal common sense and logic. With each one being the same strain that eliminates a lot of guesswork as some strains like the Sweet Tooth seem to resist everything except a chain saw!
Your soil is the same. and the water was the same and done at the same time - right?
What about your ventalation and air flow? Is that plant closest to a cooler/fan or heat vent?
Okay, I've had 2 month old plants in the same soil in ground (inside has a dirt floor) three feet apart and one decideds it's leaves need to get extra ripples in the leaves. The leaves don't look as cool as the one next to it, but the plant overall is in solid shape and has been that way for 3 weeks now. Go figure?
What I'm thinking is you might have had the light on that plant closest and the leaves didn't like it that close. Or your could have a preditor on that plant messing with the underside of the leaf? Just give it a look. It looks mostly like something chemical made the leaves turn that way - possibly not shaking your nutrients up well just before pouring.
A thousands possiblities - Bottom line - I think your plant will be fine - I wouldn't do anything drastic - JUST my opinion!
