Nutrients that the plant can move around are called mobile nutrients. Nitrogen (N), Magnesium (Mg), Phosphorous (P), Potassium (K), and Nickel (Ni) are examples. These nutrients can be cannibalized and moved to support new growth elsewhere in the plant.
Because N, P, and K are very mobile within the plant and are translocated to young leaves from old, senescing leaves, the symptoms from NPK deficiencies often first appear at the tip of the leaf and subsequently spread to the entire leaf. Under N deficiency, leaves become light green at the tip, and the color then spreads to the entire leaf. Under PK deficiencies, the symptoms are similar, and the leaf tips become yellowish brown. Therefore, the color of the leaf tip can be used to effectively identify symptoms of NPK deficiencies.
Stage is early tho.