It's gotta be mag. More pics! And yes I'm feeding them.
Roots organics go box
Bio grow 10 ml gallon
Golden tree 1-2 ml gallon
No cal mag. I usually add cal mag but this run, I wanted to try something different!
I would think two grow nutrients would be a bit much.
High calcium, high pH, high potassium, could all probably cause a magnesium lockout. I think you're supplying enough,
I don't see any other symptoms. I think calcium toxicity just looks like magnesium deficiency, due to the lockout. High pH could start showing other deficiencies.
Check soil pH.
Hit it with a foliar of epsom salts, see if the damage stops expanding.
You'll probably end up flushing and feeding, regardless.