Problem with

It looks like you have a nitrogen over fertilizer .flush the plants with water with proper ph and wait few days before adding any new fertilized water

It's all trial and error for all of us but I think it is a good idea to skip the c4 and ripener until this plant is flowering good luck with your grow 🙏

I try following the Mills schedule but may have missed a week. I have an Autoflower that’s in bloom and the one on the picture is a kosher kush, not blooming. The blooming plants don’t suffer form it, only the ones not yet in bloom. I am going to stay with a and b, skip the c4 and ripener

The Mills c4 should only be used during flower for I believe it's 3 weeks are you following the Mills feeding schedule?? As it seems you might be giving it nutrients that it doesn't need yet I personally tend to feed just under the amount the nutrient schedule suggests to begin with as it's easier to add more if needed.

Potassium deficiency. Easy on nitrogen start going to a npk ratio of 1-2-3. Is flowering requirements for cannabis. IF in coco ph between 6.2 to 6.4 is ideal.

Week 6 or so.