Have you flushed recently, if you don't add the ferts back after a flush then they will get deficient real quick. 7.6 is quite off, i wouldn't understand this unless somthing like potash had been added to the soil or somthing similar. Nute will start to get locked out, add somthing that makes the soil more acid, amonium sulphate or somthing but this could just make the problem worse.
View attachment 1663240 heres the one thats in veg, its also got like little rust spots on this leaf
I empathize but idk what the prob is
Here's a checklist of what I think it MIGHT be
N def
Overwatering
Are the yellow leaves at the bottom or top?
If at bottom it could be nute relocation which is normal
If at top it's something you either added or didn't add
Sorry I couldn't be more helpful
If in doubt, don't fert. Add a couple inches of rich composted cow manure on top of soil. Organic, non burning and your N prob will be gone. Or a nice compost tea. I'm just afraid more synthetic fertilizer might add insult to injury