Yellow spots on leaves

I have 10 plants out in the same area, getting the same sun, nutes, water, etc. The leaves on one plant have yellow spots on them. See the pictures. I've read all about nitrogen and magnessium deficiencies and this doesn't look like that. The leaves are not curling. The plant looks otherwise healthy. Anyone know what this is?

I have the same thing going on. 5 Plants getting the same sun, nutes, water, etc. And yellow spots start to appear. Everything else is fine with the plant got 5.8 ph water. 1/4 str solution since there only almost 2 weeks old. Using 4 full spectrum florescent 5850k lights. Added nutes (calmag,voodoojuice, Sensi grow A&B). Currently growing in rockwool. With a dripper system set up 10 min 3x a day. lights are on 18/6