SOIL Hello and help with brown patches

[WudsWumn]

Hello all, I've been lurking on this fabulous site since 2016, and I couldn't have set up my grow without it! But right now, I'm having a plant problem I can't diagnose from the most excellent diagnostic page here. I have a Skunk Haze plant that is failing to thrive, and it has brown patches both on the edges and on the veins. I'm posting a couple photos of leaves I took off the poor thing. Yesterday, I convinced myself it was some bug/critter and used Monterey Garden Spray (with spinosads), but it doesn't look improved yet.
I should also say, my three other plants are doing great.
I'd appreciate any help you can supply, and I look forward to getting to know y'all!
Wuds

 

[Mr.furley]

Did you splash something on the leaves with the lights on? Leaves laying on leaves before defoli?

 

[WudsWumn]

Nothing splashed under the lights, haven't needed to spritz them for some time. But the sort-of chevron pattern of brown in that last photo certainly looks like it.
Thanks Mr Furley!