This week 3 of flower
Is that a potassium issue?
Check what week your using on nutrient chart, if your feeding 1/4 then next feed do 1/2 and check again. I'd water/feed at 6.7 for a bit as well. I could be wrong but looks like the effects of over watering, make sure medium is dry before water/feeding.
Is this one plant or two different plants? Can you take a pic of the whole plant(s)? On the first pic I see white spots on the leaves which is a sign of pests. Have you inspected the plants for pests? On the second pic I see one leaf so dark and shiny that it looks like it has nitrogen toxicity. On top of that, that main leaf your showing kind of looks like phosphorus deficiency.
How does one treat nitrogen toxicity?