make sure it's not the grow lights... optical illusion etc... bc i don't see any shade of blue.
a blueish tint to leaves is caused by a P deficiency. I'd be certain before blasting it with any eleveated concentration of P though...
i guess it might be near tips on 1st / 4th pictures.
the ratio of nute mix might be a tad off but cannot be far. minor tip burn and such.. slight clawing ona couple leaves. relatively healthy is a good thing. don't react to strongly.
Phosphorus deficiency is usually listed with "blueish leaves" as a symptom. I can't necessarily see this in your photos, but just responding to your wording - you might see something we can't on the camera.