Spots on leaves

This looks like some nitrogen toxicity and nutrient burn to me. The other plant maybe eating more and able to handle it for now, but it will be getting the same issues down the road. The excess nitrogen will cause calcium to be locked out. That is a spotting on the leaves. Lower your feeds and monitor runoff of plants. it should not be to much higher then the solution going in. If it is, you have an excess of salts built up the medium and need to flush them out. Best of Luck and Happy Growing!