Some yellowing leafs 43rd day Banana Purple Punch Auto Fast Buds

the browning spots is a calcium issue. about week 4 of flowering. the plants demand calcium and magnesium. it doesnt look like too much of an issue and rhe yellowing is natural at a certain point of flower. Id just let her ride for now but in the future remember that plants do want more calcium right before the plumping stage of flowering. about week 4 when you start pk nutrients give her a shot of cal mag as well next time. just keep learning and growing and improving for next time. best of luck!

Your plant is currently in a phase where it needs increased nutrients for flowering — especially phosphorus and potassium. You might want to consider slightly increasing your nutrient dosage. However, my first impression is that this could be a calcium-magnesium (CalMag) deficiency. You didn’t mention any CalMag supplementation in your grow journal. Depending on the quality of your source water, adding CalMag might be necessary. I don’t think the issue is related to pH. With a pH-related nutrient lockout, symptoms typically don’t start on the lower leaves. In your case, the yellowing begins at the bottom, which is more characteristic of a nutrient deficiency. Do you know your water values?