The name of your thread is “what type of deficiency is this” so immediately you have planted the seed for everyone viewing it that it may be a def, and you seemed to believe it was at the time you wrote your post.
No one has said your soil/fert sucks and I’m sure it’s great for all the other plants that we aren’t here to discuss, but as for the plant in question it’s bubba kush and it needs a slightly higher PH in bloom between 6.6 to 6.8. You can never compare different plants to one another it’ll be a recipe for failure.
I truly hope you find the issue and get it figured out in time for a great yield bud.
But a nutrient deficiency is ultimately in the plant, not the soil. The soil may also be deficient and that could be the cause of a plant being deficient in nutrients. However, the deficiency is always first and foremost in the plant. A plant can experience nutrient deficiency even if the soil has plenty of nutrients in it for several possible reasons:
1. Soil pH can also cause deficiency, as you noted, it isn't just soil NPK
2. Underwatering can prevent the plant from absorbing nutrients
3. Overwatering can cause the plants roots to shield themselves from absorbing anything, resulting in nutrient deficiency
4. Excess of certain nutrients can lock other nutrients out, preventing their absorption into the plant, causing a nutrient deficiency
5. Nutrient deficiency can be caused by genetic abnormalities
6. Disease can cause nutrient deficiency
7. Soil being too compact and not aerated enough can also cause nutrient deficiency
So while it is normal for growers to immediately assume a deficiency is due to poor soil or lack of fertilizer, it simply is not always as simple as "your soil sucks bro"