White Widow gold stripes forming

I've been growing 3 white widow plants for about 2 months now. About a week ago, I noticed a gold stripe (1st pic) form on the rim of one of the leaves. Now, a week later, 2 of the 3 plants are affected by gold/yellow color and a couple wrinkles on leaves. They're beautiful and I'd hate for them to suffer from this.
Someone please help me diagnose the issue so I can fix it. I've looked at nutrient deficiency charts and am unsure of what the problem is.
I'm using FFOF soil and no nutes, as I have in my other grows, which haven't yielded significant discoloration.

Neat!

Start here
http://www.growweedeasy.com/cannabis-symptoms-pictures

Thanks for the link! It's pretty cool. I used the search engine and what I got was light burn. I turned down my 400W HPS from 100% -> 50% (28,000 lumens now) and will post again if the problem gets worse.Thank you

It's been a week, the plants have been looking MUCH worse D:
attached images show the browning leaves, leaf discoloration spreading, and smaller leaf branches falling off. Many of the leaves are "crinkly".
The last pic shows the plants where they're mostly unharmed - at their upper leaves
Any help is appreciated!!

Its a Nute burn my friend not a Light burn
Go easy on nutes. What are u feeding them?

I'm not feeding a single nute. It's only Fox Farm Ocean Forest soil and tap water, since they were seedlings. The problem is only recent... I've heard nute burn is sensitive around the early stages so idk man. thanks though!