dosent the light green leaves indicate a Nitrogen deficiency?
maybe try implementing a little veg nutes into your next feeding, not much as the plants not using alot but sometimes bloom nute lack N and end up starving the plant of Nitrogen so they take it from the leaves.
how many weeks left 3-4? or are they closer than that, hard to tell without a closeup but seems they still have lots of white pistols. buds look nice though
The trick is , feed gro nutes 2 weeks into bloom.
So that the plant uses the N for the 2 weeks it stretches during bloom
then you go 1/2 gro 3/4bloom , then all 100% bloom and mabe a shot of cal mag and micro
good to go
Since it's only 4 weeks in, the natural N deficiency shouldn't be happening. Throw a tiny amount of veg nutes into your next feeding just to give it some nitrogen and see how she responds.