One of the LSD plants has some rust spots appearin...

Hey there so I'm having a similar problem with one of my plants. A leaf that is rusty spotting etc. I believe my problem is due to the plant beginning to outgrow the container and overwatering(poor drainage, circulation). Therefore causing unfortunate root troubles and nute uptake problems. although giving your basic nutes should provide the necessary items, if they're locked out it'll make no difference until remedied. All of your information looks pretty good, so if you attempt the cal mag and it doesn't fix it, try looking into these other potential issues. Happy growing :)

Hello there! What I see is necrotic brown spots between your leaves veins. It looks like a boron deficiency. Does her upper leaves display abnormal/slow growth? Are the stems becoming rough/hollow? Do you use RO water to feed her? Has your plant been underwatered for a few hours? How stable are your grow room conditions? I'll be around, good luck with these babies!