I know you probably already figured it out, or others did. I haven't gone throug the whole journal, but what you thought was manganese was most likely potasium K. manganese MN, starts from the center and goes outward, that is, the yellow starts from the center and moves outward. K, starts from the tips of the leaves and moves down. Both give spots on the leaves. Or rather K starts more on the outer parts or tips or both.