Is this a Deficiency or pests? I don't see any mites or at least not that I can see on the underside. I am growing in fox farms and used no nutes just recharge
Of course, since that's the main pest I've gotten, I always think thrips.
You're in veg, so there are a variety of safe ways to kill them. You'll have to hit them twice, about 3 days apart. Maybe a third time for good measure.