The extremely strong sativa phenotype of this plan...

I would recommend you give your plants a flush. Check the runoff ph and ppms to see what you get. If you have ppms over 1600 (0.5 scale tds meter) flush her a bit more. If shes really low like under 800 ppm it could be your underfeeding. It's also possible you may have an abundance of one element blocking absoption of another. So either way a good flush will get you back on track. Too much calcium will block potassium absorption. Add your nutes to the last half gallon of flush water. Then let her dry out a bit more than usual before your next watering/feeding. I would recommend adding some type of pk booster to help bulk up those buds. GH has some good products or even Canna PK 13/14 would be a good choice. You will see the most bulking up in the last few weeks of bloom. Lastly adapt a strict wet then dry type watering cycle to maximize the roots ability to absorb nutrients and try to check your runoff ppms to know where you stand. You should see some results in a week or two of doing this. Hope this helps.