I wouldn't start over-finishing this grow is a valuable learning experience. If you are using a complete 2 part like Jacks (or even 1 part like Maxibloom), you just won't see deficiencies like these if you are feeding over 500 ppm (which is LOW, most ppl feed 700+ in flower.) I didn't catch if you're using soil or coco, but I would double check everything at this point. Make sure your PH and TDS pens are accurate, do a slurry test on your media to see what is happening there, then I'd raise the PPMs of the nutrient solution and adjust it to 5.8 to start.