Same strain, very different look - nitrogen issues?

Both of these are white-widow autoflowers on week 6 to the day.

From the beginning the plant on the left has grown taller despite using same light and exact same, fairly minimum, nutrient regime. Left plant has many more tall bud sites and they're really long. It's leaves are, in general, smaller the the guy on the right.

Starting 2-3 days ago the leaves near the bud (Which are tiny) have been drooping. After googling like crazy a couple days ago I *think* it's nitrogen toxicity? (Or is it deficiency?).

I've tried a flush yesterday, just water, and really doused it. For the next 12 hours things improved (the drooping leaves started standing up a little) but now it's back to where it was yesterday. Hence I finally created a rollitup account and am bringing the pic here.

What do you all think problem is and what do I do?

Why is it so different than the other? Same seeds. Maybe they sent a different strain? They look nothing alike to me...

Edit: I've got them on 18/6 with a 1000W LED. I rotate position daily. I am following this guide to a T

Alright, I am beginning to think that this is NOT N-toxicity but overwatering. Thoughts?

It sucks that they look so similar since N-toxicity cure is "water it more". I think when I tried to flush it I might have done more harm than good because the bottom leaves are even more yellow now and almost dead.