Hey there CannabisTrope, I cant really say for sure 100% because you're not showing me your feed or your pH, but I'm seeing the symptoms of the very start of a phosphorous deficiency. You can tell from the "splotchy-style" deficiency you're seeing , this might get worse and turn colorful. Just make sure your "high K feed" also has an appropriate P content for a good NPK ratio during flower. You caught the thing very early so hopefully the plant will recover quickly. Hope this helps ! đ