Help 1st grow, What are these symptoms of?

First grow, Diesel Auto, Leaves showing some light blotches. What do you think this is a sign of? My other plants in the same grow space are not showing these symptoms, or maybe they are but it is extremely minor and not noticeable.. Any thoughts? Thanks in advance. The plant is about 3 weeks old.

More details: Using LED lights, about 48 inches above the canopy. Three lights, one 450w+ viparspectra and two 150W cheap UFO's. Temps stay 68-74F at night cycle, 72-81F during the day cycle. Humidity is at about 60-70% (now it is, I was having low humidity problems last week before humidifier arrived). Carbon filters + fans on each end. Water is PH'd Correctly, I got a bluelab pen just to make sure. Was feeding only distilled water, last week realized I need at least calmag+Iron. I have a feeling this was the problem, but Have been feeding them this for the last week with no noticeable improvements, new growth still is showing signs of these blotches. bottom 50% Fox Farm Ocean Forest soil, top 50% light warrior seedling soil. Growth was stunted at 1.5 week when my cat learned to unzip and enter my tent, trampling her... If you want any more info let me know! Trying to get to the bottom of this, thanks.

I know, she is already starting to flower and is probably too stunted to get a good yield, just trying to troubleshoot what's going on with her leaves. Thanks!

Hard to tell in the light but shading looks possible magnesium deficiency.

Those were my thoughts as well. I got botanicare calmag+, started feeding it about a week ago, so hopefully the newer growth will look better. I have 2 other diesel auto's on the same feeding regimen and they arent showing any of the same leaf blotching, but I guess this could be due to variance in genetics?